The world's greatest cycling race spends most of its three weeks and 3,664 kilometers (2,277 miles) in France, but occasionally holds a few of its 21 stages outside the country. This year's event kicked off Saturday with two days in the hills and dales of Yorkshire in northern England. On Monday, competitors race from Cambridge to London, where they are guaranteed a warm welcome.
Here are five things to know before the peloton sweeps through the British capital.
'VIVE LA FRANCE' A LONDRES
London is home to as many as 300,000 French people and Mayor Boris Johnson has claimed it is the sixth-biggest French city.
London's French residents range from students and artists to Internet entrepreneurs and bankers fleeing France's high tax rates on the wealthy. The city has French bakeries, bookshops and kindergartens, as well as French-speaking dentists and plumbers. In 2012, a Londoner was even elected to the French legislature - Axelle Lemaire.
LONDON LOVES LE TOUR
Londoners love a chance to get outside and cheer, whether it's a marathon or a royal wedding. When the Tour's kickoff, the "Grand Depart," came to London in 2007, 1 million people lined the streets.
That event gave a big boost to British cycling and an infusion of national lottery cash has helped make the country a powerhouse in the sport. U.K. cycling heroes include sprint ace Mark Cavendish, six-time Olympic gold medalist Chris Hoy and two Tour de France champions - 2012 winner Bradley Wiggins and 2013 champ Chris Froome.
Froome, of Team Sky, is one of the favorites to win again this year.
LONDON IS A CYCLING CAPITAL
London is famous for black cabs, red buses - and blue bikes.
The city launched a cycle-sharing program in 2010 modeled on Paris's Velib scheme. London's 10,000 rental cycles are a common sight on the streets, used by commuters and tourists alike - and dubbed "Boris Bikes" after the cycle-loving mayor.
While London's frenetic traffic can be daunting, thousands of people commute by bike each day. They include Prime Minister David Cameron, who before he moved to Downing Street was known to pedal to Parliament from his west London home.
Cameron is part of a growing social group - MAMILS, or middle-aged men in lycra.
BICYCLES ARE BRITISH
The origins of the bicycle are contested, but if Britain didn't invent the bike, it was crucial to its development. The earliest versions of the two-wheeled vehicle required riders to propel it along the ground with their feet. In the 1830s, a Scottish blacksmith named Kirkpatrick MacMillan had a dash of inspiration and added pedals.
By the late 19th century, Britain was a major bike manufacturer, with companies such as Rover and Raleigh sending cycles around the world. The vast majority of bikes are now made overseas, but Britain is still home to successful cycle firms, including folding-bike manufacturer Brompton.
BRITAIN CHERISHES A CHARACTER
Competitive cycling abounds with the sort of dogged, even eccentric, individuals that Britons adore.
The sport's popularity in Britain owes a lot to Wiggins - not just a champion but a character, with his sideburns, Mod fashions and love of a pint or two.
Publicity around the Tour is leading Britons to rediscover unsung cycling heroes such as Beryl Burton, the subject of a new play. An indomitable Yorkshire native who funded her sport by picking rhubarb, Burton was Britain's greatest 1960s and '70s cyclist, a five-time world pursuit champion and holder of numerous records - including, for two years, the men's 12-hour time trial record.
Burton died of heart failure in 1996 while delivering invitations by bike for her 59th birthday party.