Kef Toghobeit Cave
Kef Toghobeit is a karst cave near the settlement of Bab Taza in Chefchaouen Province, Tanger-Tetouan-Al Hoceima, in northern Morocco. Currently known to be long and deep, it is the deepest cave in Morocco, and the third deepest cave in Africa.
Although Kef Toghobeit has been well-explored, its full extent is not yet known. Indeed, the karst topography of the Rif mountain range where the cave begins has barely been mapped - just 1000 caves are known in Morocco, and the geology would suggest that more than this exist.
Canyon
The Yarlung Tsangpo Grand Canyon (or Tsangpo Canyon), along the Yarlung Tsangpo River in Tibet, is regarded by some as the deepest canyon in the world at 5,500 m (18,000 ft). It is slightly longer than the Grand Canyon in the United States. Others consider the Kali Gandaki Gorge in midwest Nepal to be the deepest canyon, with a 6400 m (21,000 ft) difference between the level of the river and the peaks surrounding it.