A walk through this deep fissure of rock, running for 11 miles (17 km) from Omalos to Aghia Roumeli on the south coast of Crete, is not for the unfit. Once in the gorge, there’s no turning back. It’s a Dantean landscape of sheer rock rising towards the sun, which in high summer shines without mercy. Towards the end, the rock walls are 1,640 ft (500 m) high.
The Samariá Gorge is a National Park of Greece since 1962 on the island of Crete – a major tourist attraction of the island – and a World’s Biosphere Reserve. The gorge is in southwest Crete in the regional unit of Chania. It was created by a small river running between the White Mountains (Lefká Óri) and Mt. Volakias.
There are a number of other gorges in the White Mountains. While some say that the gorge is 18 km long, this distance refers to the distance between the settlement of Omalos on the northern side of the plateau and the village of Agia Roumeli. In fact, the gorge is 16 km long, starting at an altitude of 1,250 m at the northern entrance, and ending at the shores of the Libyan Sea in Agia Roumeli. Wikipedia