This castle is above the village of Agia Roumeli, at the exit of the Samaria gorge. You can reach it through an uphill path that will reward your efforts with a magnificent view towards the sea.
These types of fortresses were built by the Ottomans to control the Cretan revolutions in 1866 and 1869. In this way, they could oversee the area, both the sea and the hinterland. In 1867 and 1868 the Ottomans attacked the refuge of the revolutionaries, at the entrance of the Samaria gorge. Following that, they established four such fortresses in the broader area. The one above Agia Roumeli is the best preserved among those. It is a big, rectangular building, with a bastion to its west and two round towers.