Finca El Paraíso hot waterfall, near Río Dulce

A natural hot spring that pours over a waterfall into a cool river pool, so you can stand under steaming hot water while swimming in cold water: an unusual and wonderful experience. It's on a farm on the road between Río Dulce and El Estor, near Lake Izabal.

For the adventurous, follow the river upstream for about 45 minutes to a large cave, known to locals but not in most guidebooks, which the river flows out of. Bring a waterproof torch and swim inside: the cave goes on for hundreds of metres, with underground waterfalls and stalactites, and some climbing and swimming. Go with someone who knows the way.

There's a small entry fee. Take a bus or minibus from Río Dulce (Fronteras) towards El Estor and ask to get off at Finca El Paraíso, about 45 minutes.