Since the UK's busiest airport began operation in 1946 over 20 million flights have taken off from there, with more than two billion passengers travelling around the world.
New York, Dublin and Dubai have been the most commonly visited cities from Heathrow.
The airport has hosted many memorable moments, from the Beatles returning to the UK as superstars in 1964 to the England rugby team arriving home as World Cup winners in 2003.
In 1952 the former Princess Elizabeth stepped onto UK soil for the first time as monarch at Heathrow. Her father, King George VI, had died while she was touring Kenya.
For her part, Joanna Lumley is no stranger to Heathrow.
Lumley, who turned 70 on 1 May, travelled from there to Nepal in 2009 while leading the campaign to allow Gurkhas settlement rights in Britain.
The actress said: "It's such an honour to celebrate the 70th anniversary of Heathrow, an airport that has played host to some of the world's most amazing journeys.
"I have travelled through Heathrow for work, pleasure and for trips close to my heart, with my travels to Nepal being some of the most precious moments of my life."
Heathrow chief executive John Holland-Kaye said: "We're very proud of the role the airport has played in millions of people's lives as well as the economic success of the UK.
"This is an occasion for everyone to celebrate how Heathrow's global connections have influenced our nation and to recognise the possibilities of those journeys yet to come."
Australian airline Qantas is marking Heathrow's anniversary with a competition offering 35 pairs of return flights to Sydney and five nights' accommodation.