Which is the toughest cycling competition: the Tour the France, the Giro d'Italia or the Vuelta a España?

Cycling

The Tour de France, the Giro d'Italia and the Vuelta a España are the most important three-week cycling races in Europe. They have a long history and attract the best teams and riders in the world. Legendary cyclists like Hinault, Merckx and Indurain made history on some of the most iconic stages such as those finishing at Alpe-d'Huez, Tourmalet, Passo di lo Stelvio, Mortirolo, Angliru or Lagos de Covadonga. However they are different views regarding the difficulty of these races.

Tour, Giro or Vuelta, which cycling race is the toughest in your opinion? Vote here and share examples about past races that illustrate how difficult they are.