Starting at Chichen Itza, there's a lot to do in the Yucatan Peninsula in Mexico. The Temple of Kukulcan or La Pyramid was built by the Mayans in honor to their Serpent God. And it's one of the most interesting places to understand a bit of this ancient culture.
After that you may see some big different water sites like the Cenotes, or caves filled with water where you can swim and Las Coloradas - the pinky salty waters where Mexicans extract salt to use.
For some adventure Jumelanio, Lambisgoio and Xilosfenio went on Wave Runners to exploit the Lagoons and the Reefs by the Sea in Cancun.
In Yucatan for the first time they Scuba Dive in the waters of Cozumel where they had the opportunity to explore the reefs, see fishes, turtles and the vast wild life under water.