The Serre Chevalier Altitude Challenge features 5 timed mountain bike ascents for gravel and road bikes. Riders can tackle the climbs in any order, embracing the "holy war against gravity." Descent times are not recorded, allowing participants to enjoy the UNESCO-classified Vauban forts. Whether on tarmac or "wild paths," the challenge remains intense. A "natural cryotherapy session" in the Durance river follows the effort.