On Sunday we went to the world-famous XCaret “eco theme park”, really more like an aquarium-zoo-beach (no roller coasters or anything like that!), quite unusual and really wonderful.
The highlight of XCaret is the “underground river” which is freezing, but once you get over that, it is pretty amazing; about an hour floating through caves from one end of the park to the other. They also have an awesome beach there.
Sam and I also did Snuba, which is kind of a cross between snorkelling and scuba (you have an air tank, so you can stay under indefinetely, but you are anchored to the surface by hoses and can’t descend more than about 20′, which is plenty for a wuss like me).