Approximately half of all international travellers arrive first in Australia in Sydney, the largest city, (IATA: SYD; ICAO: YSSY). After Sydney, significant numbers of travellers also arrive in Australia in Melbourne, Brisbane, Perth and Cairns. There are also direct international services into Adelaide, Darwin, the Gold Coast and Christmas Island though these are largely restricted to flights from New Zealand or Southeast Asia. To Sydney it is a 3-hour flight from New Zealand, a 7-11 hour flight from countries in Asia, a 14 hour flight from the west of the United States of America and Canada, a 14 hour flight from Johannesburg, South Africa, a 13-16 hours flight from South America, and up to a 24+ hour flight from western Europe. On account of long journey times from some destinations, some travellers from Europe opt to have a stop-over, commonly in Singapore, Hong Kong, Dubai, Bangkok or Kuala Lumpur. If you have to change to a domestic flight in a gateway city, Sydney, Brisbane and Perth all have distinct domestic terminals, requiring some time and complexity to transit, check the guides. Melbourne, Adelaide, Darwin, Cairns and the Gold Coast have all gates in the one terminal building or within easy walking distance of each other.