Sumela Monastery in Turkey - is built on a cliff, around a cave and hanging over a precipice. It was originally built in 386 by two Athenian priests and has fallen into ruin several times. In spite of restoration plans, the ruins remain primarily untouched.
Geghard Monastery, Armenia The monastery of Geghard (Armenian: Գեղարդ, meaning spear) is a unique architectural construction in the Kotayk province of Armenia, being partially carved out of the adjacent mountain, surrounded by cliffs. It is listed as a UNESCO World Heritage Site. While the main chapel was built in 1215, the monastery complex was founded in the 4th century by Gregory the Illuminator at the site of a sacred spring inside a cave.
The Library of Celsus in Ephesus was built in 117 A.D as a tomb for Gaius Julius Celsus Polemaeanus, the governor of the province of Asia. The capacity of the library was more than 12,000 scrolls. It was the third richest library in ancient times after the ones in Alexandria and Pergamum.The Library of Celsus in Ephesus, Izmir Province, Turkey (by ozmen70).
Corfe Castle is a fortification standing above the village of the same name in the English county of Dorset. Built by William the Conqueror, the castle dates back to the 11th century. The castle underwent two sieges - the first, in 1643, was unsuccessful, but the second was successful and ended in an assault. In March that year Corfe Castle was demolished on Parliament's orders.