Return time zone list. See below example:
 
$list = App::Helper('Date')->getTimeZoneList();

pre($list);

/*
Array
(
    [Africa/Abidjan] => Africa/Abidjan
    [Africa/Accra] => Africa/Accra
    [Africa/Addis_Ababa] => Africa/Addis_Ababa
    [Africa/Algiers] => Africa/Algiers
    [Africa/Asmara] => Africa/Asmara
    [Africa/Asmera] => Africa/Asmera
    [Africa/Bamako] => Africa/Bamako
    [Africa/Bangui] => Africa/Bangui
    [Africa/Banjul] => Africa/Banjul
    [Africa/Bissau] => Africa/Bissau
    [Africa/Blantyre] => Africa/Blantyre
    [Africa/Brazzaville] => Africa/Brazzaville
    [Africa/Bujumbura] => Africa/Bujumbura
    [Africa/Cairo] => Africa/Cairo
    [Africa/Casablanca] => Africa/Casablanca
    [Africa/Ceuta] => Africa/Ceuta
    [Africa/Conakry] => Africa/Conakry
    [Africa/Dakar] => Africa/Dakar
    [Africa/Dar_es_Salaam] => Africa/Dar_es_Salaam
    [Africa/Djibouti] => Africa/Djibouti
    [Africa/Douala] => Africa/Douala
    [Africa/El_Aaiun] => Africa/El_Aaiun
    [Africa/Freetown] => Africa/Freetown
    [Africa/Gaborone] => Africa/Gaborone
    [Africa/Harare] => Africa/Harare
    [Africa/Johannesburg] => Africa/Johannesburg
    [Africa/Kampala] => Africa/Kampala
    [Africa/Khartoum] => Africa/Khartoum
    [Africa/Kigali] => Africa/Kigali
    [Africa/Kinshasa] => Africa/Kinshasa
    [Africa/Lagos] => Africa/Lagos
    [Africa/Libreville] => Africa/Libreville
    [Africa/Lome] => Africa/Lome
    [Africa/Luanda] => Africa/Luanda
    [Africa/Lubumbashi] => Africa/Lubumbashi
    [Africa/Lusaka] => Africa/Lusaka
    [Africa/Malabo] => Africa/Malabo
    [Africa/Maputo] => Africa/Maputo
    [Africa/Maseru] => Africa/Maseru
    [Africa/Mbabane] => Africa/Mbabane
    [Africa/Mogadishu] => Africa/Mogadishu
    [Africa/Monrovia] => Africa/Monrovia
    [Africa/Nairobi] => Africa/Nairobi
    [Africa/Ndjamena] => Africa/Ndjamena
    [Africa/Niamey] => Africa/Niamey
    [Africa/Nouakchott] => Africa/Nouakchott
    [Africa/Ouagadougou] => Africa/Ouagadougou
    [Africa/Porto-Novo] => Africa/Porto-Novo
    [Africa/Sao_Tome] => Africa/Sao_Tome
    [Africa/Timbuktu] => Africa/Timbuktu
    [Africa/Tripoli] => Africa/Tripoli
    [Africa/Tunis] => Africa/Tunis
    [Africa/Windhoek] => Africa/Windhoek
    [America/Adak] => America/Adak
    [America/Anchorage] => America/Anchorage
    [America/Anguilla] => America/Anguilla
    [America/Antigua] => America/Antigua
    [America/Araguaina] => America/Araguaina
    [America/Argentina/Buenos_Aires] => America/Argentina/Buenos_Aires
    [America/Argentina/Catamarca] => America/Argentina/Catamarca
    [America/Argentina/ComodRivadavia] => America/Argentina/ComodRivadavia
    [America/Argentina/Cordoba] => America/Argentina/Cordoba
    [America/Argentina/Jujuy] => America/Argentina/Jujuy
    [America/Argentina/La_Rioja] => America/Argentina/La_Rioja
    [America/Argentina/Mendoza] => America/Argentina/Mendoza
    [America/Argentina/Rio_Gallegos] => America/Argentina/Rio_Gallegos
    [America/Argentina/Salta] => America/Argentina/Salta
    [America/Argentina/San_Juan] => America/Argentina/San_Juan
    [America/Argentina/San_Luis] => America/Argentina/San_Luis
    [America/Argentina/Tucuman] => America/Argentina/Tucuman
    [America/Argentina/Ushuaia] => America/Argentina/Ushuaia
    [America/Aruba] => America/Aruba
    [America/Asuncion] => America/Asuncion
    [America/Atikokan] => America/Atikokan
    [America/Atka] => America/Atka
    [America/Bahia] => America/Bahia
    [America/Barbados] => America/Barbados
    [America/Belem] => America/Belem
    [America/Belize] => America/Belize
    [America/Blanc-Sablon] => America/Blanc-Sablon
    [America/Boa_Vista] => America/Boa_Vista
    [America/Bogota] => America/Bogota
    [America/Boise] => America/Boise
    [America/Buenos_Aires] => America/Buenos_Aires
    [America/Cambridge_Bay] => America/Cambridge_Bay
    [America/Campo_Grande] => America/Campo_Grande
    [America/Cancun] => America/Cancun
    [America/Caracas] => America/Caracas
    [America/Catamarca] => America/Catamarca
    [America/Cayenne] => America/Cayenne
    [America/Cayman] => America/Cayman
    [America/Chicago] => America/Chicago
    [America/Chihuahua] => America/Chihuahua
    [America/Coral_Harbour] => America/Coral_Harbour
    [America/Cordoba] => America/Cordoba
    [America/Costa_Rica] => America/Costa_Rica
    [America/Cuiaba] => America/Cuiaba
    [America/Curacao] => America/Curacao
    [America/Danmarkshavn] => America/Danmarkshavn
    [America/Dawson] => America/Dawson
    [America/Dawson_Creek] => America/Dawson_Creek
    [America/Denver] => America/Denver
    [America/Detroit] => America/Detroit
    [America/Dominica] => America/Dominica
    [America/Edmonton] => America/Edmonton
    [America/Eirunepe] => America/Eirunepe
    [America/El_Salvador] => America/El_Salvador
    [America/Ensenada] => America/Ensenada
    [America/Fort_Wayne] => America/Fort_Wayne
    [America/Fortaleza] => America/Fortaleza
    [America/Glace_Bay] => America/Glace_Bay
    [America/Godthab] => America/Godthab
    [America/Goose_Bay] => America/Goose_Bay
    [America/Grand_Turk] => America/Grand_Turk
    [America/Grenada] => America/Grenada
    [America/Guadeloupe] => America/Guadeloupe
    [America/Guatemala] => America/Guatemala
    [America/Guayaquil] => America/Guayaquil
    [America/Guyana] => America/Guyana
    [America/Halifax] => America/Halifax
    [America/Havana] => America/Havana
    [America/Hermosillo] => America/Hermosillo
    [America/Indiana/Indianapolis] => America/Indiana/Indianapolis
    [America/Indiana/Knox] => America/Indiana/Knox
    [America/Indiana/Marengo] => America/Indiana/Marengo
    [America/Indiana/Petersburg] => America/Indiana/Petersburg
    [America/Indiana/Tell_City] => America/Indiana/Tell_City
    [America/Indiana/Vevay] => America/Indiana/Vevay
    [America/Indiana/Vincennes] => America/Indiana/Vincennes
    [America/Indiana/Winamac] => America/Indiana/Winamac
    [America/Indianapolis] => America/Indianapolis
    [America/Inuvik] => America/Inuvik
    [America/Iqaluit] => America/Iqaluit
    [America/Jamaica] => America/Jamaica
    [America/Jujuy] => America/Jujuy
    [America/Juneau] => America/Juneau
    [America/Kentucky/Louisville] => America/Kentucky/Louisville
    [America/Kentucky/Monticello] => America/Kentucky/Monticello
    [America/Knox_IN] => America/Knox_IN
    [America/La_Paz] => America/La_Paz
    [America/Lima] => America/Lima
    [America/Los_Angeles] => America/Los_Angeles
    [America/Louisville] => America/Louisville
    [America/Maceio] => America/Maceio
    [America/Managua] => America/Managua
    [America/Manaus] => America/Manaus
    [America/Marigot] => America/Marigot
    [America/Martinique] => America/Martinique
    [America/Matamoros] => America/Matamoros
    [America/Mazatlan] => America/Mazatlan
    [America/Mendoza] => America/Mendoza
    [America/Menominee] => America/Menominee
    [America/Merida] => America/Merida
    [America/Mexico_City] => America/Mexico_City
    [America/Miquelon] => America/Miquelon
    [America/Moncton] => America/Moncton
    [America/Monterrey] => America/Monterrey
    [America/Montevideo] => America/Montevideo
    [America/Montreal] => America/Montreal
    [America/Montserrat] => America/Montserrat
    [America/Nassau] => America/Nassau
    [America/New_York] => America/New_York
    [America/Nipigon] => America/Nipigon
    [America/Nome] => America/Nome
    [America/Noronha] => America/Noronha
    [America/North_Dakota/Center] => America/North_Dakota/Center
    [America/North_Dakota/New_Salem] => America/North_Dakota/New_Salem
    [America/Ojinaga] => America/Ojinaga
    [America/Panama] => America/Panama
    [America/Pangnirtung] => America/Pangnirtung
    [America/Paramaribo] => America/Paramaribo
    [America/Phoenix] => America/Phoenix
    [America/Port-au-Prince] => America/Port-au-Prince
    [America/Port_of_Spain] => America/Port_of_Spain
    [America/Porto_Acre] => America/Porto_Acre
    [America/Porto_Velho] => America/Porto_Velho
    [America/Puerto_Rico] => America/Puerto_Rico
    [America/Rainy_River] => America/Rainy_River
    [America/Rankin_Inlet] => America/Rankin_Inlet
    [America/Recife] => America/Recife
    [America/Regina] => America/Regina
    [America/Resolute] => America/Resolute
    [America/Rio_Branco] => America/Rio_Branco
    [America/Rosario] => America/Rosario
    [America/Santa_Isabel] => America/Santa_Isabel
    [America/Santarem] => America/Santarem
    [America/Santiago] => America/Santiago
    [America/Santo_Domingo] => America/Santo_Domingo
    [America/Sao_Paulo] => America/Sao_Paulo
    [America/Scoresbysund] => America/Scoresbysund
    [America/Shiprock] => America/Shiprock
    [America/St_Barthelemy] => America/St_Barthelemy
    [America/St_Johns] => America/St_Johns
    [America/St_Kitts] => America/St_Kitts
    [America/St_Lucia] => America/St_Lucia
    [America/St_Thomas] => America/St_Thomas
    [America/St_Vincent] => America/St_Vincent
    [America/Swift_Current] => America/Swift_Current
    [America/Tegucigalpa] => America/Tegucigalpa
    [America/Thule] => America/Thule
    [America/Thunder_Bay] => America/Thunder_Bay
    [America/Tijuana] => America/Tijuana
    [America/Toronto] => America/Toronto
    [America/Tortola] => America/Tortola
    [America/Vancouver] => America/Vancouver
    [America/Virgin] => America/Virgin
    [America/Whitehorse] => America/Whitehorse
    [America/Winnipeg] => America/Winnipeg
    [America/Yakutat] => America/Yakutat
    [America/Yellowknife] => America/Yellowknife
    [Antarctica/Casey] => Antarctica/Casey
    [Antarctica/Davis] => Antarctica/Davis
    [Antarctica/DumontDUrville] => Antarctica/DumontDUrville
    [Antarctica/Mawson] => Antarctica/Mawson
    [Antarctica/McMurdo] => Antarctica/McMurdo
    [Antarctica/Palmer] => Antarctica/Palmer
    [Antarctica/Rothera] => Antarctica/Rothera
    [Antarctica/South_Pole] => Antarctica/South_Pole
    [Antarctica/Syowa] => Antarctica/Syowa
    [Antarctica/Vostok] => Antarctica/Vostok
    [Arctic/Longyearbyen] => Arctic/Longyearbyen
    [Asia/Aden] => Asia/Aden
    [Asia/Almaty] => Asia/Almaty
    [Asia/Amman] => Asia/Amman
    [Asia/Anadyr] => Asia/Anadyr
    [Asia/Aqtau] => Asia/Aqtau
    [Asia/Aqtobe] => Asia/Aqtobe
    [Asia/Ashgabat] => Asia/Ashgabat
    [Asia/Ashkhabad] => Asia/Ashkhabad
    [Asia/Baghdad] => Asia/Baghdad
    [Asia/Bahrain] => Asia/Bahrain
    [Asia/Baku] => Asia/Baku
    [Asia/Bangkok] => Asia/Bangkok
    [Asia/Beirut] => Asia/Beirut
    [Asia/Bishkek] => Asia/Bishkek
    [Asia/Brunei] => Asia/Brunei
    [Asia/Calcutta] => Asia/Calcutta
    [Asia/Choibalsan] => Asia/Choibalsan
    [Asia/Chongqing] => Asia/Chongqing
    [Asia/Chungking] => Asia/Chungking
    [Asia/Colombo] => Asia/Colombo
    [Asia/Dacca] => Asia/Dacca
    [Asia/Damascus] => Asia/Damascus
    [Asia/Dhaka] => Asia/Dhaka
    [Asia/Dili] => Asia/Dili
    [Asia/Dubai] => Asia/Dubai
    [Asia/Dushanbe] => Asia/Dushanbe
    [Asia/Gaza] => Asia/Gaza
    [Asia/Harbin] => Asia/Harbin
    [Asia/Ho_Chi_Minh] => Asia/Ho_Chi_Minh
    [Asia/Hong_Kong] => Asia/Hong_Kong
    [Asia/Hovd] => Asia/Hovd
    [Asia/Irkutsk] => Asia/Irkutsk
    [Asia/Istanbul] => Asia/Istanbul
    [Asia/Jakarta] => Asia/Jakarta
    [Asia/Jayapura] => Asia/Jayapura
    [Asia/Jerusalem] => Asia/Jerusalem
    [Asia/Kabul] => Asia/Kabul
    [Asia/Kamchatka] => Asia/Kamchatka
    [Asia/Karachi] => Asia/Karachi
    [Asia/Kashgar] => Asia/Kashgar
    [Asia/Kathmandu] => Asia/Kathmandu
    [Asia/Katmandu] => Asia/Katmandu
    [Asia/Kolkata] => Asia/Kolkata
    [Asia/Krasnoyarsk] => Asia/Krasnoyarsk
    [Asia/Kuala_Lumpur] => Asia/Kuala_Lumpur
    [Asia/Kuching] => Asia/Kuching
    [Asia/Kuwait] => Asia/Kuwait
    [Asia/Macao] => Asia/Macao
    [Asia/Macau] => Asia/Macau
    [Asia/Magadan] => Asia/Magadan
    [Asia/Makassar] => Asia/Makassar
    [Asia/Manila] => Asia/Manila
    [Asia/Muscat] => Asia/Muscat
    [Asia/Nicosia] => Asia/Nicosia
    [Asia/Novokuznetsk] => Asia/Novokuznetsk
    [Asia/Novosibirsk] => Asia/Novosibirsk
    [Asia/Omsk] => Asia/Omsk
    [Asia/Oral] => Asia/Oral
    [Asia/Phnom_Penh] => Asia/Phnom_Penh
    [Asia/Pontianak] => Asia/Pontianak
    [Asia/Pyongyang] => Asia/Pyongyang
    [Asia/Qatar] => Asia/Qatar
    [Asia/Qyzylorda] => Asia/Qyzylorda
    [Asia/Rangoon] => Asia/Rangoon
    [Asia/Riyadh] => Asia/Riyadh
    [Asia/Saigon] => Asia/Saigon
    [Asia/Sakhalin] => Asia/Sakhalin
    [Asia/Samarkand] => Asia/Samarkand
    [Asia/Seoul] => Asia/Seoul
    [Asia/Shanghai] => Asia/Shanghai
    [Asia/Singapore] => Asia/Singapore
    [Asia/Taipei] => Asia/Taipei
    [Asia/Tashkent] => Asia/Tashkent
    [Asia/Tbilisi] => Asia/Tbilisi
    [Asia/Tehran] => Asia/Tehran
    [Asia/Tel_Aviv] => Asia/Tel_Aviv
    [Asia/Thimbu] => Asia/Thimbu
    [Asia/Thimphu] => Asia/Thimphu
    [Asia/Tokyo] => Asia/Tokyo
    [Asia/Ujung_Pandang] => Asia/Ujung_Pandang
    [Asia/Ulaanbaatar] => Asia/Ulaanbaatar
    [Asia/Ulan_Bator] => Asia/Ulan_Bator
    [Asia/Urumqi] => Asia/Urumqi
    [Asia/Vientiane] => Asia/Vientiane
    [Asia/Vladivostok] => Asia/Vladivostok
    [Asia/Yakutsk] => Asia/Yakutsk
    [Asia/Yekaterinburg] => Asia/Yekaterinburg
    [Asia/Yerevan] => Asia/Yerevan
    [Atlantic/Azores] => Atlantic/Azores
    [Atlantic/Bermuda] => Atlantic/Bermuda
    [Atlantic/Canary] => Atlantic/Canary
    [Atlantic/Cape_Verde] => Atlantic/Cape_Verde
    [Atlantic/Faeroe] => Atlantic/Faeroe
    [Atlantic/Faroe] => Atlantic/Faroe
    [Atlantic/Jan_Mayen] => Atlantic/Jan_Mayen
    [Atlantic/Madeira] => Atlantic/Madeira
    [Atlantic/Reykjavik] => Atlantic/Reykjavik
    [Atlantic/South_Georgia] => Atlantic/South_Georgia
    [Atlantic/St_Helena] => Atlantic/St_Helena
    [Atlantic/Stanley] => Atlantic/Stanley
    [Australia/ACT] => Australia/ACT
    [Australia/Adelaide] => Australia/Adelaide
    [Australia/Brisbane] => Australia/Brisbane
    [Australia/Broken_Hill] => Australia/Broken_Hill
    [Australia/Canberra] => Australia/Canberra
    [Australia/Currie] => Australia/Currie
    [Australia/Darwin] => Australia/Darwin
    [Australia/Eucla] => Australia/Eucla
    [Australia/Hobart] => Australia/Hobart
    [Australia/LHI] => Australia/LHI
    [Australia/Lindeman] => Australia/Lindeman
    [Australia/Lord_Howe] => Australia/Lord_Howe
    [Australia/Melbourne] => Australia/Melbourne
    [Australia/NSW] => Australia/NSW
    [Australia/North] => Australia/North
    [Australia/Perth] => Australia/Perth
    [Australia/Queensland] => Australia/Queensland
    [Australia/South] => Australia/South
    [Australia/Sydney] => Australia/Sydney
    [Australia/Tasmania] => Australia/Tasmania
    [Australia/Victoria] => Australia/Victoria
    [Australia/West] => Australia/West
    [Australia/Yancowinna] => Australia/Yancowinna
    [Brazil/Acre] => Brazil/Acre
    [Brazil/DeNoronha] => Brazil/DeNoronha
    [Brazil/East] => Brazil/East
    [Brazil/West] => Brazil/West
    [CET] => CET
    [CST6CDT] => CST6CDT
    [Canada/Atlantic] => Canada/Atlantic
    [Canada/Central] => Canada/Central
    [Canada/East-Saskatchewan] => Canada/East-Saskatchewan
    [Canada/Eastern] => Canada/Eastern
    [Canada/Mountain] => Canada/Mountain
    [Canada/Newfoundland] => Canada/Newfoundland
    [Canada/Pacific] => Canada/Pacific
    [Canada/Saskatchewan] => Canada/Saskatchewan
    [Canada/Yukon] => Canada/Yukon
    [Chile/Continental] => Chile/Continental
    [Chile/EasterIsland] => Chile/EasterIsland
    [Cuba] => Cuba
    [EET] => EET
    [EST] => EST
    [EST5EDT] => EST5EDT
    [Egypt] => Egypt
    [Eire] => Eire
    [Etc/GMT] => Etc/GMT
    [Etc/GMT+0] => Etc/GMT+0
    [Etc/GMT+1] => Etc/GMT+1
    [Etc/GMT+10] => Etc/GMT+10
    [Etc/GMT+11] => Etc/GMT+11
    [Etc/GMT+12] => Etc/GMT+12
    [Etc/GMT+2] => Etc/GMT+2
    [Etc/GMT+3] => Etc/GMT+3
    [Etc/GMT+4] => Etc/GMT+4
    [Etc/GMT+5] => Etc/GMT+5
    [Etc/GMT+6] => Etc/GMT+6
    [Etc/GMT+7] => Etc/GMT+7
    [Etc/GMT+8] => Etc/GMT+8
    [Etc/GMT+9] => Etc/GMT+9
    [Etc/GMT-0] => Etc/GMT-0
    [Etc/GMT-1] => Etc/GMT-1
    [Etc/GMT-10] => Etc/GMT-10
    [Etc/GMT-11] => Etc/GMT-11
    [Etc/GMT-12] => Etc/GMT-12
    [Etc/GMT-13] => Etc/GMT-13
    [Etc/GMT-14] => Etc/GMT-14
    [Etc/GMT-2] => Etc/GMT-2
    [Etc/GMT-3] => Etc/GMT-3
    [Etc/GMT-4] => Etc/GMT-4
    [Etc/GMT-5] => Etc/GMT-5
    [Etc/GMT-6] => Etc/GMT-6
    [Etc/GMT-7] => Etc/GMT-7
    [Etc/GMT-8] => Etc/GMT-8
    [Etc/GMT-9] => Etc/GMT-9
    [Etc/GMT0] => Etc/GMT0
    [Etc/Greenwich] => Etc/Greenwich
    [Etc/UCT] => Etc/UCT
    [Etc/UTC] => Etc/UTC
    [Etc/Universal] => Etc/Universal
    [Etc/Zulu] => Etc/Zulu
    [Europe/Amsterdam] => Europe/Amsterdam
    [Europe/Andorra] => Europe/Andorra
    [Europe/Athens] => Europe/Athens
    [Europe/Belfast] => Europe/Belfast
    [Europe/Belgrade] => Europe/Belgrade
    [Europe/Berlin] => Europe/Berlin
    [Europe/Bratislava] => Europe/Bratislava
    [Europe/Brussels] => Europe/Brussels
    [Europe/Bucharest] => Europe/Bucharest
    [Europe/Budapest] => Europe/Budapest
    [Europe/Chisinau] => Europe/Chisinau
    [Europe/Copenhagen] => Europe/Copenhagen
    [Europe/Dublin] => Europe/Dublin
    [Europe/Gibraltar] => Europe/Gibraltar
    [Europe/Guernsey] => Europe/Guernsey
    [Europe/Helsinki] => Europe/Helsinki
    [Europe/Isle_of_Man] => Europe/Isle_of_Man
    [Europe/Istanbul] => Europe/Istanbul
    [Europe/Jersey] => Europe/Jersey
    [Europe/Kaliningrad] => Europe/Kaliningrad
    [Europe/Kiev] => Europe/Kiev
    [Europe/Lisbon] => Europe/Lisbon
    [Europe/Ljubljana] => Europe/Ljubljana
    [Europe/London] => Europe/London
    [Europe/Luxembourg] => Europe/Luxembourg
    [Europe/Madrid] => Europe/Madrid
    [Europe/Malta] => Europe/Malta
    [Europe/Mariehamn] => Europe/Mariehamn
    [Europe/Minsk] => Europe/Minsk
    [Europe/Monaco] => Europe/Monaco
    [Europe/Moscow] => Europe/Moscow
    [Europe/Nicosia] => Europe/Nicosia
    [Europe/Oslo] => Europe/Oslo
    [Europe/Paris] => Europe/Paris
    [Europe/Podgorica] => Europe/Podgorica
    [Europe/Prague] => Europe/Prague
    [Europe/Riga] => Europe/Riga
    [Europe/Rome] => Europe/Rome
    [Europe/Samara] => Europe/Samara
    [Europe/San_Marino] => Europe/San_Marino
    [Europe/Sarajevo] => Europe/Sarajevo
    [Europe/Simferopol] => Europe/Simferopol
    [Europe/Skopje] => Europe/Skopje
    [Europe/Sofia] => Europe/Sofia
    [Europe/Stockholm] => Europe/Stockholm
    [Europe/Tallinn] => Europe/Tallinn
    [Europe/Tirane] => Europe/Tirane
    [Europe/Tiraspol] => Europe/Tiraspol
    [Europe/Uzhgorod] => Europe/Uzhgorod
    [Europe/Vaduz] => Europe/Vaduz
    [Europe/Vatican] => Europe/Vatican
    [Europe/Vienna] => Europe/Vienna
    [Europe/Vilnius] => Europe/Vilnius
    [Europe/Volgograd] => Europe/Volgograd
    [Europe/Warsaw] => Europe/Warsaw
    [Europe/Zagreb] => Europe/Zagreb
    [Europe/Zaporozhye] => Europe/Zaporozhye
    [Europe/Zurich] => Europe/Zurich
    [Factory] => Factory
    [GB] => GB
    [GB-Eire] => GB-Eire
    [GMT] => GMT
    [GMT+0] => GMT+0
    [GMT-0] => GMT-0
    [GMT0] => GMT0
    [Greenwich] => Greenwich
    [HST] => HST
    [Hongkong] => Hongkong
    [Iceland] => Iceland
    [Indian/Antananarivo] => Indian/Antananarivo
    [Indian/Chagos] => Indian/Chagos
    [Indian/Christmas] => Indian/Christmas
    [Indian/Cocos] => Indian/Cocos
    [Indian/Comoro] => Indian/Comoro
    [Indian/Kerguelen] => Indian/Kerguelen
    [Indian/Mahe] => Indian/Mahe
    [Indian/Maldives] => Indian/Maldives
    [Indian/Mauritius] => Indian/Mauritius
    [Indian/Mayotte] => Indian/Mayotte
    [Indian/Reunion] => Indian/Reunion
    [Iran] => Iran
    [Israel] => Israel
    [Jamaica] => Jamaica
    [Japan] => Japan
    [Kwajalein] => Kwajalein
    [Libya] => Libya
    [MET] => MET
    [MST] => MST
    [MST7MDT] => MST7MDT
    [Mexico/BajaNorte] => Mexico/BajaNorte
    [Mexico/BajaSur] => Mexico/BajaSur
    [Mexico/General] => Mexico/General
    [NZ] => NZ
    [NZ-CHAT] => NZ-CHAT
    [Navajo] => Navajo
    [PRC] => PRC
    [PST8PDT] => PST8PDT
    [Pacific/Apia] => Pacific/Apia
    [Pacific/Auckland] => Pacific/Auckland
    [Pacific/Chatham] => Pacific/Chatham
    [Pacific/Easter] => Pacific/Easter
    [Pacific/Efate] => Pacific/Efate
    [Pacific/Enderbury] => Pacific/Enderbury
    [Pacific/Fakaofo] => Pacific/Fakaofo
    [Pacific/Fiji] => Pacific/Fiji
    [Pacific/Funafuti] => Pacific/Funafuti
    [Pacific/Galapagos] => Pacific/Galapagos
    [Pacific/Gambier] => Pacific/Gambier
    [Pacific/Guadalcanal] => Pacific/Guadalcanal
    [Pacific/Guam] => Pacific/Guam
    [Pacific/Honolulu] => Pacific/Honolulu
    [Pacific/Johnston] => Pacific/Johnston
    [Pacific/Kiritimati] => Pacific/Kiritimati
    [Pacific/Kosrae] => Pacific/Kosrae
    [Pacific/Kwajalein] => Pacific/Kwajalein
    [Pacific/Majuro] => Pacific/Majuro
    [Pacific/Marquesas] => Pacific/Marquesas
    [Pacific/Midway] => Pacific/Midway
    [Pacific/Nauru] => Pacific/Nauru
    [Pacific/Niue] => Pacific/Niue
    [Pacific/Norfolk] => Pacific/Norfolk
    [Pacific/Noumea] => Pacific/Noumea
    [Pacific/Pago_Pago] => Pacific/Pago_Pago
    [Pacific/Palau] => Pacific/Palau
    [Pacific/Pitcairn] => Pacific/Pitcairn
    [Pacific/Ponape] => Pacific/Ponape
    [Pacific/Port_Moresby] => Pacific/Port_Moresby
    [Pacific/Rarotonga] => Pacific/Rarotonga
    [Pacific/Saipan] => Pacific/Saipan
    [Pacific/Samoa] => Pacific/Samoa
    [Pacific/Tahiti] => Pacific/Tahiti
    [Pacific/Tarawa] => Pacific/Tarawa
    [Pacific/Tongatapu] => Pacific/Tongatapu
    [Pacific/Truk] => Pacific/Truk
    [Pacific/Wake] => Pacific/Wake
    [Pacific/Wallis] => Pacific/Wallis
    [Pacific/Yap] => Pacific/Yap
    [Poland] => Poland
    [Portugal] => Portugal
    [ROC] => ROC
    [ROK] => ROK
    [Singapore] => Singapore
    [Turkey] => Turkey
    [UCT] => UCT
    [US/Alaska] => US/Alaska
    [US/Aleutian] => US/Aleutian
    [US/Arizona] => US/Arizona
    [US/Central] => US/Central
    [US/East-Indiana] => US/East-Indiana
    [US/Eastern] => US/Eastern
    [US/Hawaii] => US/Hawaii
    [US/Indiana-Starke] => US/Indiana-Starke
    [US/Michigan] => US/Michigan
    [US/Mountain] => US/Mountain
    [US/Pacific] => US/Pacific
    [US/Pacific-New] => US/Pacific-New
    [US/Samoa] => US/Samoa
    [UTC] => UTC
    [Universal] => Universal
    [W-SU] => W-SU
    [WET] => WET
    [Zulu] => Zulu
)
*/