You can spend the night in a fairytale castle that has its own underground ‘sunken grotto’ pool

THE world is full of amazing places to go for a dip, but one spot really is a 'hidden' gem - as you can swim underneath a castle. The Château d'Urspelt, in the heart of the Éislek region of Luxembourg, is a luxurious hotel within a former castle. But below it is the ultimate surprise...