The Mayan civilization lasted more than 2,500 years. Left behind are over 4,000 archeological sites. The most famous and visited ancient cities in the northern Yucatán Peninsula are Chichén Itzá and Tulum. However, the tallest pyramid in the region at 138 feet is Ixmoja at Coba, Mexico. Also called Nohoch Mul, this stepped pyramid measures almost 200 feet at the base. The surrounding ruins provide hints of what this city looked like when it was populated by 50,000 people.