Chris Froome, bidding for a record-equalling fifth title, and 175 other riders set off on the first stage of the 2018 Tour de France on Saturday from the island of Noirmoutier off the Atlantic coast.
Cycling fans packed the roadsides of the 201km (125-mile) ride to Fontenay-le-Comte, the stage looking certain to end with a sprint finish around 1400 GMT.
There was a festive family atmosphere on the mainly coastal route, which was well marshalled by a massive police presence that organisers hope will deter fans targeting Froome, who was only cleared to race last week after long-running suspicions of doping were put to bed.
Saturday's Grand Depart for a much-awaited 21-day slog around France comes in two distinct and thrilling phases.
The 105th edition of cycling's greatest race set off from the picturesque Atlantic island of Noirmoutier, connected to the mainland by an enormous road bridge.
The peloton of 22 teams of eight riders will then race along the windswept coastline famous for attracting vast crowds of yachting enthusiasts for the Vendee Globe around-the-world race that also sets off there.
Team Sky's Froome, his fellow riders and the organisers are all reeling from the tempestuous run-up to the Tour, which culminated Thursday with the four-time winner being roundly booed at the official presentation.
The 33-year-old Kenyan-born Briton went as far as appealing for understanding and belief from the French public in the pages of newspaper Le Monde on Friday.
The hope is that once it starts, the focus will switch to interest in the race, and Saturday's run along the coast will prove or disprove that idea.
The stage is expected to culminate in a sprint finish, with Briton Mark Cavendish targeting a 31st stage win, but winds are expected and a surprise may be in store.
The winner gets 10 bonus seconds and will have the honour of pulling on one of the greatest prizes in cycling, the overall leader's yellow jersey, with Germany's Marcel Kittel the bookies' favourite.
The first nine days of racing take in the West and North of France with Monday's 35.5km team time-trial setting the agenda.
The peloton will then hop on flights to the Alpine town of Annecy, where Froome, the great French hope Romain Bardet, 2014 champion Vincenzo Nibali and the other climb specialists will start to plot each other's downfall.
The gruelling climb mayhem begins with three visually stunning Alpine mountain stages, four hilly stages and three Pyrenean mountain stages inside a breathless 12 days.
But the two key challenges are a brutal, uphill 31km individual time trial and a short, sharp shock of a 17th stage with just 65km, featuring 25km of hair-raising descents and 38km of climbs to a summit finish at the Col de Portet in the southwest.