Mexico’s Riviera Maya has undergone a building ... But the UNESCO designated Sian Ka’an Biosphere Reserve is pure, unadulterated nature: 1,305,082 acres of tropical forests and mangroves ...

In 1986, Mexico declared the area a protected reserve. The following year, it became a UNESCO World Heritage Site named Sian Ka'an, roughly translated as "the place where the sky was born" in Mayan.