The "Sian Ka'an Biosphere Reserve" is one of the world's largest natural reserve, its name means "where the sky is born" in the language of the Mayan people who once inhabited this region. It's located in a place where Jungle, marshes and a large marine section with a barrier reef all meets. One of the most untouched and pure place I've ever been in this planet.
We walked inside the jungle ( foreground ) to get to the dock further down to take the boat tour around the lagoon..
The massive mangrove forest inside the lagoon. The mangrove grows in clean water.
We took a tour with only one more couple from Rome that day. Getting wet in a fast boat ride.
A man-made building in the middle of lagoons. It was originally built around 900AD in order to prevent any outsider to invade.