Mausoleum, one of the Seven Wonders of the World, was built in Halicarnassus. The marble stones of the mausoleum, which was destroyed by the effects of earthquakes and invasions over time, were used in the construction of Bodrum Castle. The castle was built in the 15th century by the Christian Knights. Construction was completed in 100 years. The Pope distributed indulgences to those who worked in the construction of the castle. The city of Bodrum was the last Christian land seized in Anatolia. Although the city was besieged during the reign of Mehmet II, it could only be seized during the Rhodes Expedition by the Sultan Suleyman the Magnificent. Today, Bodrum Castle serves as the 2nd largest Underwater Archeology Museum in the world. It is the strongest surviving castle in the Eastern Mediterranean. The city of Bodrum hosts many cultural events.