After our visit to Tulum in the morning, the day trip also included a visit to Xel-Ha.  Xel-ha is a recreational site where visitors can explore a multitude of natural wonders including a labrynth of waterways and paths through the tropical jungle, lagoons of transparent turquoise water, private inlets and coves, cenotes (fresh water sinkholes or natural wells), a cool river which flows through a mangrove forest, multicolored fish, and a verdant lush jungle.  They also have a stable of dolphins that visitors can actually swim with.