The most common Medieval wonders are the Catacombs of Kom el Shoqafa, the Colosseum, the Great Wall of China, the Hagia Sophia, the Leaning Tower of Pisa, the Porcelain Tower of Nanjing, and Stonehenge. Others that typically make these lists are the Cairo Citadel, Cluny Abbey, Ely Cathedral, and the Taj Mahal.