For gorge Mont-Rebei can freely say that is the most beautiful canyon in the world. It is located in Catalonia, Spain on river Noguera Ribagorçana. If you want to move through this gorge must go on foot, there is no railways and roads. The walls are located at a height of 500 meters and a width of 20 meters diameter. source
There is another way in which you can pass the gorge, was discovered in 1984, although it was known before. This road is in the middle of the vertical wall and above the maximum level of the water. For this gorge is characteristic that has 1640 foot walls with limestone and embedded roads for visitors. The vegetation of the gorge is divided into two zones: Southern slope where dominated dry steppe shrubs, oak trees and Euro-Siberian vegetation of sub-Mediterranean nature, with prevalence of small oak forests.