This UNESCO World Heritage site sprawls on 1.3 million acres and contains ecosystems that include lowland forests, flooded savannahs, mangroves and coastal barrier reefs. On the Muyil Forest and Float, walk through the jungle (bring bug spray) to view several Maya ruins, including the impressively tall El Castillo. Afterward, board a boat for a ride through the canals of the flooded savannahs. When you reach the mangroves, jump in the canal for a fun float behind your boat. Community Tours’ guides are naturalists from the local Maya communities. Reserve ahead.