Stay on the Plaza San Diego in a 17th-century former nunnery in Cartagena’s historic quarter. You can still explore its hallowed hidden staircases and chapel, and the restaurant, 1621, is a reminder of the year the building was completed. Guests can also dine and drink at El Claustro, under cloister vaults, and in El Coro Lounge Bar, above a crypt. There are newer wings too, and a chic pool area. Choose a suite for butler service and one on the top floor bedrooms for sea views (you can see for 500 miles on a clear day).