The Unbreakable Galle Fort

The beautiful city of Galle in Sri Lanka has a rich history of trade and foreign occupation. Before 1400, it was a popular harbor for Persians, Chinese, Malays, Arabs, Greeks, Indians and other powerful nations.

For monks without vertigo

The Holy Trinity Monastery in Kalabaka, Greece is an Eastern Orthodox monastery, built in the 1400s as part of some 24 other monasteries. It is built on top of a rocky precipice, which is around 400 meters (1200ft) high.

Marib, the Kingdom of Saba and the Worlds oldest dam

At one point in time, Marib (in present day Yemen) was the capital of the Kingdom of Saba, which is mentioned in Christian, Jewish and Islamic texts. This city is also the site of the Marib Dam which blocked the Wadi Adhanah river and is the oldest known dam in the World.

Derinkuyu: Ancient Underground City

In 1969, a large underground city was rediscovered in Derinkuyu, Turkey.  It was built in approximately 800 – 700 BC and contains an intricate system of tunnels and several dozens of rooms up to 60 meters (196 ft) deep.