The Ionospheric Observatory is the largest and one of the most important research facilities of its kind on earth. Hike to the viewing platform to see the huge dish, which could fit more than a dozen football fields inside it, shimmering in the sun. The visitor centre has some striking interactive exhibits.
By car: Road 22, then Road 134 followed by Road 635 and follow signs; one hour plus.
El Yunque Rain Forest
Named after a benevolent Indian spirit, this is the only rainforest in the US National Forest System. With 240 species of tree, it is a series of forests, of varying altitude. A spectacular 100 billion gallons of rain fall each year, creating the jungle-like ambience of lush foliage, sparkling leaves, shining wet rocks and shadowy paths, occasionally pierced by sunlight. You can follow one of the many trails or go on a guided tour with a ranger.
By car: Road 26 towards Carolina, then Road 3 towards Fajardo and Road 191; journey time about one hour.
Camuy Cave Park
This dramatic cave system has an underground river thundering through it. Ride a trolley that descends into a sink-hole lined with dense vegetation while a guide describes the sights. After a walk through the dramatically lit cave, another tram shuttles you to a platform overlooking the 400ft-deep Tres Pueblos sink-hole. Don't miss the ancient rock carvings.
By car: Road 22 towards Arecibo, then Road 129 and follow signs; one hour plus.
Pinones Natural Reserve
Stretches of deserted beach plus a maze of mangroves, thick forest, dramatic dunes and extraordinary wildlife. Twitchers can record up to 46 species of bird and snorkellers can see 36 species of fish. Continue east and you will soon reach Valcia Talega Beach and its strange landscape of twisted rocks dotted with palm trees.
By car: Road 26 towards Carolina, then Road 187 and follow signs; about 30 mins.
Bacardi Rum distillery
The "Cathedral of Rum" is one of Puerto Rico's most popular attractions. Take a guided tour past vast fermentation vats and bottling machinery and see the lofty, bat-like pavilion where you can stock up on, and sample, the rum.
By car: Highway 22 west, then Road 165 and follow signs; approx 20 mins.
No trip to Puerto Rico is complete without hitting the kiosks. There are some 80 or 90 kiosks along the roadside, music thundering from nearly all of them as the mouth-watering aromas of fried seafood and coconut candy waft through the air.
By car: east on Road 3 towards Luquillo; about 45 mins.
Harlequin Worldwide Travel (017098 850300; www.harlequinholidays.com) offers a seven-night b&b break at the four-star El Convento Hotel from £1,078 per person, based on two sharing, including flights. Car hire costs from £30 per day. Contact Puerto Rico Tourism (01932 253302; www.GoToPuertoRico.com).Reuse content