Suq al-Wadi, Yemen
This massive palace was originally built as a summer home for the King of Yemen in the 1930s. Nothing says summer getaway like a house carved from the surrounding rock cliffs with seven stories and 35 rooms, right? Unfortunately for the Iman, he never spent much time in the palace because he was assassinated only a few years later. Dar Al Hajar is currently owned by the Yemeni government and is a popular tourist attraction.