Belgian Jasper Philipsen won his second successive Tour de France stage amid scenes of chaos as several riders hit the ground on the final circuit on Tuesday.
Australian Caleb Ewan took second place and German Phil Bauhaus finished third in the fourth stage, a 182-kilometer ride from Dax, with Briton Adam Yates retaining the overall leader's yellow jersey.
After the peloton rode at a snail's pace most of the day, things got hectic in the finale on the Paul Armagnac racing track, near the vineyards that once belonged to 1973 Tour champion Luis Ocana of Spain.