London Heathrow is the main international airport in the United Kingdom. Heathrow is the  busiest airport in Europe by passenger traffic and the third busiest airport in the world by total passenger traffic, handling more international passengers than any other airport around the globe. In 2013, it handled 72,3 million passengers. Heathrow is the primary hub for British Airways and the primary operating base for Virgin Atlantic.
Heathrow Airport started in 1929 as a small airfield on land south-east of the hamlet of Heathrow from which the airport takes its name.
Source: Wikipedia