The Samaria Gorge is 16 kilometers, starting from an altitude of 1250 meters and reaches down to the shores of the Libyan Sea in Agia Roumeli. The distance you need to drive in the gorge of Samaria is 13 km (but will need to drive and others 3 km to Agia Roumeli).
The very narrow passage near the end of the gorge called the "iron gate". Nobody knows where he got the name.
The Samaria Gorge is the longest of the whole of Europe and one of the longest gorges in the world! Samaria Gorge National Park is located in Samaria, in the White Mountains in western Crete.