It’s not only slippery cobblestones that pose a danger to tour riders. Human error, slick surfaces, battles for position and potholes are just a few of the risks that riders face. Some accidents result in fatalities – 139 during races since 1894 – according to Wikipedia.

Stan Ockers hit his peak at the ripe old age of 35. In 1955, this all-rounder won the Ardennes classics La Fleche Wallonne and Liege-Bastogne-Liege as well as the world championship. The following year, the Belgian cycling hero crashed at a track event in Antwerp and died two days later in hospital.

The Olympic road race in Rome in 1960 was held at temperatures in excess of 40 degrees Celcius (104 Fahrenheit) and Knud Enemark Jensen suffered heat stroke. As a result he fell off his bike and fractured his skull – dying in hospital a day later. His coach admitted that Jensen had been doping and a toxicological report confirmed this. Doping tests had not yet been introduced at the Olympics.

Joaquim Agostinho was a Portuguese folk hero, having participated in the Tour de France 13 times and even winning the stage on Alpe d'Huez in 1979. In 1984, while leading the Tour of the Algarve, Agostinho was caused to crash by the presence of a dog. Ten days later he died of the head injuries he had suffered in the crash.

During the 1995 Tour de France, Fabio Casartelli fell from his bike and hit his head on a concrete road barrier. The Tour doctor managed to revive the Italian, but Casatelli later succumbed to his injuries. There is now a monument to Casartelli at the scene of the accident.

It may seem unthinkable today but for years professional cyclists didn’t wear helmets. This changed after Kazakhstan’s Andrei Kivilev collided with two other riders during the Paris-Nice race, hitting his head on the ground and falling into a coma. He died shortly afterwards. As a result, cycling’s world governing body, the UCI, made the wearing of helmets compulsory in all of its events.

One of the darkest days in the history of the Giro d‘Italia: In 2011 Wouter Weylandt lost control of his bike on the descent from the Bocca Pass – he touched a wall with one of his pedals and was thrown across the road, crashing face first. Despite immediate attempts to revive him the Belgian died at the scene of the crash.

What exactly caused Antoine Demoitie’s death remains unclear. The Belgian cyclist collided with four other riders 150 kilometers (93 miles) into in the 2016 edition of the Gent-Wevelgem race – before an escort motorbike hit him. The 25-year-old later died of a cerebral hemorrhage but the autopsy was unable to determine whether this was due to the collision with the other riders or the motorcycle.

The injuries he sustained in the crash pictured above forced Spaniard David Canada to pull out of the 2006 Tour de France but he was able to continue his career as a professional rider until 2009. In 2016, he took part in an amateur race in his home region of Aragon, collided with another competitor, crashed and died of his head injuries.

The latest fatal crash in professional cycling: The 22-year-old Belgian was considered a rising star in the cycling world. During the 2019 Tour de Pologne, Lambrecht rode into a ditch and died in the hospital that same evening.