Colca Canyon may be the region's most famous natural attraction, but at 3,354 meters (11,001 feet), Cotahuasi is the world's deepest gorge, beating Colca Canyon by 163 meters (534 feet). It's nearly twice as deep as the Grand Canyon. The canyon has been carved by the Río Cotahuasi, which becomes the Río Ocuña before connecting to the Pacific. Its deepest point is at Ninochaco, below the quaint administrative capital of Quechualla and accessible only by kayak. Kayak explorations first documented the area in the mid-1990s and measured its depth. Since then, paddling the Cotahuasi River's Class V rapids is to kayakers what scaling Mount Everest is to mountaineers.
The ride from Arequipa to the Cotahuasi Canyon ranks with the great scenic roads of the world. As you pass Corire and Toro Muerto, the road rides the western side of snow-capped Nevado Coropuno (6,424 meters, 21,076 feet), Peru's third-highest mountain, for spectacular views as you descend into the valley of Cotahuasi. Logistically speaking, it's a bumpy 11- to 13-hour bus ride or 10 hours by four-wheel drive from Arequipa. The pavement ends in Chuquibamba, but some of the road from there to Cotahuasi, the longest stretch of the ride, is in the process of being graded. There's no fee to enter the canyon.