Xcaret Park is a huge eco-adventure park near Cancun where you can swim in underground rivers, see animals like jaguars and sea turtles, and watch shows about Mexican culture. It's like a mix of nature and history. It is roughly an hour away from the resort. Bring swimsuits/water shoes.
Chichén Itzá is an ancient Mayan city in Mexico, famous for its massive pyramid, El Castillo. It’s one of the New Seven Wonders of the World and a must-see if you're into history or cool ruins. Its two and a half hours from the resort. Will not be a lot of cover so bring an umbrella/hat/sunscreen if you burn easily. Wear comfortable shoes.