When seaweed hits the coast of the riviera maya it gets difficult to find a spot to go for a swim without getting exposed to the rotten smell and dirt. An amazing alternative are cenotes. A cenote is a natural pit, or sinkhole, resulting from the collapse of limestone bedrock that exposes groundwater. There are more than 6000 cenotes on the peninsula which offer fresh water for a swim and some of them have underwater caves to dive in.