Heathrow Airport is a major international airport in London, United Kingdom. Heathrow is the third busiest airport in the world by international passenger traffic (surpassed by Dubai International in 2014, and Hong Kong International in 2016), as well as the busiest airport in Europe by passenger traffic, and the sixth busiest airport in the world by total passenger traffic. In 2016, it handled a record 75.7 million passengers, a 1.0% increase from 2015.
Heathrow lies 14 miles (23 km) west of Central London, and has two parallel east–west runways along with four operational terminals on a site that covers 12.27 square kilometers (4.74 sq mi).
Heathrow Airport has 5 terminals - Terminal 1 is currently closed due to refurbishment
International connections do not require going through Immigration but all International to Domestic connections do. Domestic to International connecting passengers can use special Immigration check points if baggage is already checked.