Tulum, Mexico, is a town on the Yucatán Peninsula's Caribbean coast. It is a popular tourist destination due to its beautiful beaches and well-preserved Mayan port city ruins. The main edifice is a massive stone castle-like structure known as El Castillo, and it sits atop a cliff overlooking the beach and the azure water below. Parque Nacional Tulum, a coastal area with mangroves and cenotes, is located close to the ruins (natural limestone sinkholes).