The fortress of Eger is located east of the town on a hillside. Its actual location was not ideal from a military point of view - the castle overlooks only the southern and western parts of the walled town - however, it had the advantage over the Ottoman forces as it provided excellent locations for gun positions. The castle comprised an inner and outer fortress with a gate tower to the southeast and 6 bastions on the walls - the Earth Bastion and Prison Bastion to the northwest, Sándor Bastion on the north wall, Bolyky Bastion on the northeast corner, Bebek Bastion on the eastern corner of the outer fortress and the Dobó Bastion on the western wall. The Varkoch gate sat on the southern wall of the inner fortress while a further bastion, Church Bastion, lay at the centre of the wall separating the two parts of the fortress. The fortress of Eger was built on the ruins of an earlier stone fort, which replaced an ancient earthen encampment, possibly erected by the Huns. This made Eger's foundations stronger than usual and greatly hindered the work of Ottoman miners. As was usual during sieges at that time, both the attackers and the defenders tried to dug tunnels under the walls and plant gunpowder charges to either open gaps into the fortress or destroy the attacker's trenches. None of these attempts were successful during the siege of Eger.