At Aslanlı Kapı, two stone lions (one rather poorly reconstructed) protect the city from evil spirits. This is one of at least six gates in Hattuşa's 4000-year-old defensive walls, though it may never have been completed. You can see the best-preserved parts of Hattuşa's fortifications from here, stretching southeast to Yer Kapı and from there to Kral Kapı.
The walls illustrate the Hittites' engineering ingenuity, which enabled them to either build in sympathy with the terrain or transform the landscape, depending on what was required. Natural outcrops were appropriated as part of the walls, and massive ramparts were built to create artificial fortresses.