The ruins of Chichen Itza are quite possibly the best Mayan ruins in the Yucatan Peninsula - the site is vast and many of the structures are still in tact. It was also an important site in Mayan history during its heyday as an ancient Mayan city of nearly 50,000 people. That said, Tulum has some of the most beautiful Mayan ruins thanks to its position just above the stunning turquoise water. It's also much closer to visit for travelers staying along Riviera Maya.