No matter where you are in Puerto Rico, you're never more than a couple of hours by car from San Juan , whose colonial architecture in its old town is a must-see. More historic vestiges can be found in the southern city of Ponce .

Hikers won't want to miss El Yunque , the only tropical rainforest in the US park system, with miles of trails, and flora and fauna galore. Birdwatching is also excellent in the arid landscape of Guánica State Forest , a World Biosphere Reserve in the southwest.

Puerto Rico is also home to pretty beaches and coral reefs; for diving and snorkelling check out the beautiful offshore islets of Vieques and Culebra .

If you prefer going underground, rather than underwater, spelunkers from all over the globe are drawn to the Río Camuy Cave Park in the northwest, known as karst country - where limestone has eroded over the centuries to form sinkholes and a vast network of caves that can be explored.