From the 6C-10C, Barbarian hordes threatened Cappadocia, forcing the locals underground. Whole underground cities were built, replicating their world above ground, with chapels, halls, latrines and storerooms. The entrance to these hidden cities is usually an almost invisible hole. One of Cappadocia's main attractions, there are thought to be around 150 such underground cities. The most excavated are Derinkuyu and Kaymakli, the largest.