Nature places in Central America
The Manatee is a strange looking sea creature best described as a sea cow. It eats seaweed and normally weighs 500 kg which should make it easy to see, but no. Gales Point, though, is a great place to spot these creatures since the offshore hot spring is a hang-out for them. The watching is done from a small boat (no swimming or snorkelling is allowed) and don't expect to see more than a head coming up for air. But hey, this is wildlife.
The Mayans believed that a cave was the pathway to the underworld, a connection to the Gods. The cave at Barton Creek is a wet cave (water is dripping from the roof and a creek flows trough it) and was therefore thought to belonged to the rain God, Chac. So to make him happy and get a good harvest, they sacrificed what Mayan Gods apparently wanted: humans. Today, the tour into the cave is done by canoe with one of the park rangers acting as a guide. Bits and pieces of Mayan artefacts (including a skull) have been laid out to be viewed from the canoe, but you don't get on land to see the actual sacrificing place where the bones are. If Mayan bones are more your thing, you might want to try the more expensive Actun Tunichil Muknal cave (ATM cave) further east which requires hiking, scrambling and swimming to get to.
Be prepared for some wet and misty weather here in highlands of Costa Rica. Dense cloud forest are covering the hills and two nature reserves are taken up a good part of the area. Great jungle walks criss-cross the reserves, but keep in mind that catching sight of anything slightly exotic like a quetzal or toucan need patience and luck (a good nature guide also helps). It is a great place to escape the heat down at the coast for it gets chilly up here. The adrenalin junkies can enjoy the forest a bit from above by flying through the canopy hanging from wires on one of the many canopy tours, don't miss the "Super Man" (head first slide).
A deep cave with fairly impressive stalactites. The first section is lighted and deeper exploration is possible but the cave isn't really the attraction here, it is the bats. At dusk thousands of fruit bats (though we didn't counted) leave the cave to go hunt for food. They all exit at the mouth of the cave where it is possible to stand and experience the bat exodus from the inside of the cave. In the dark you can feel the animals navigating centimetres from your head but amazingly never collide with you (or each other). A flash from your camera will reveal how dense the air is with bats.
Every night from July to January tens, even hundreds, of sea turtles come out of the ocean and crawl laboriously up on the beach for lay their eggs. About six weeks later hundreds of small baby turtles dicking themselves out of the sand and rush to sea. This beach is a wet dream for any animal lover and an unique opportunity to experience the endangered Leatherback which still comes here to nest, though most of the sea turtles are of the Olive Ridley species. Though the beach is protected by the military and rangers there are few limitations for visitors, so please act responsible and do not disturb the turtles in any way. Visiting turtle sites (when done right) can actually help saving them, since the "tourist money" can give poor local communities a reason to protect the sea turtles.