Tumba del Caracol is a Mayan building found on the southern end of Cozumel, erected during the post-classic period. There are a couple of legends concerning the buildings. One is that it functioned as a weather alarm, producing a whistle via conch shells that would precede the arrival of a hurricane, The other is that the building was used to send a pillar of smoke into the air so that travelers could find their way back to the island, the later is more believable because of the Maya ruins found at San Gervasio. Those ruins were believed to be the home of some sort of fertility ritual, those ruins are unique to Mayan culture as there are no signs that any human sacrifices had taken place there.
Photos copyright paper-dragon, 2018