Cenotes (sinkholes) are deep wells with crystal clear water that can be accessed when the roof of a cave collapses. Fed by underground rivers, the cenotes were the main source of freshwater for the Mayans and therefore are considered sacred. They are unique to the Yucatán peninsula, and still to this day, the underground cave system connecting all the cenotes remains largely unexplored. Witnessing the breathtaking beauty of the large clusters of stalactites and stalagmites being mirrored in the crystal clear cool waters is a unique experience. Every cenote has its own particular beauty, and putting on a swimsuit and snorkeling in the pool is an absolutely unforgettable experience. Some tour operators also offer cave diving excursions for very experienced divers.

The best sandy beach in the region can be found just south of this pretty fishing port on Apulia's west coast, about 80 km (50 miles) south of Brindisi, where yet another medieval castle guards a fine natural harbour overlooked by old whitewashed houses. Gallipoli has plenty of places to stay suiting all budgets and some excellent fish restaurants.

Step on board on a boat for a trip to Gothenburg’s most westerly outpost — the lighthouse Vinga. The beautiful island offers a unique natural setting with fantastic waters for swimming. The Swedish singer and composer Evert Taube grew up here when his father was the lighthouse keeper from 1890 onward. Today, their house is a museum and you can join a guided tour for a fascinating glimpse into early 19th-century life.