My most recent trip to Puerto Rico was very different from my first visit to the island more than five years ago. Perhaps because we never left San Juan that first time, we never got the opportunity to savor the personality and variety of the island.

Obviously, there is much more to the island than the big city, home to a million and a half people and, frankly, some of the least interesting beaches on the island.I am happy to report that there is a second Puerto Rico burgeoning on both the Atlantic and the Caribbean sides of the island. Distinctly tropical and peaceful, the island has many spots that are typical oases of the most classic Caribbean vacation.

Roaming across the island, from the lush and mountainous interior to the seductive beaches, is a feast for all the senses. Farmers set up rickety roadside stands near pineapple groves, ready to cut up one of the luscious fruits for you with a sharp machete. It's fun to let the sticky pineapple juice run down your face as you try to get at all the sweetness. But roadside stands that sell cooked food should be avoided, no matter how savory the smells. Sanitary conditions at roadside stands cannot be monitored.

From the limestone caves at Rio Camuy to the rain forest high atop El Yunque, the island provides fresh challenges to the vacationer, not just to roast on the beach or wander across some of the spanking-new golf courses, but to visit some of the island's many relatively unknown natural spots.

For the last decade or so, Puerto Rico has been eclipsed as a warm-weather destination by seemingly more exotic spots in the Caribbean - St. Barths, the Cayman Islands and St. John, to name a few. Having traveled to many islands in this alluring part of the world, I can say that Puerto Rico has many charms of its own - both exotic and practical - that may have been forgotten.

Americans have come to view the Caribbean in a rather one-dimensional way. We have treated this sunny and inviting part of our hemisphere as little more than a place to bake in the sun and drink cocktails made from local rum and pineapples.

But Puerto Rico is a historic place - Christopher Columbus visited the island in 1493, claiming it for Spain. In 1898, the Spanish ceded the island, along with the Philippines, to the United States.

Long before that, the tiny island was a strategic spot. For more than 500 years, the island was Spain's military headquarters in the Caribbean. Old San Juan has been sitting on the top of a promontory since the 1520s, and the walled city was the scene of many battles involving the Dutch, Spanish and British. Today Old San Juan, the oldest city under the U.S. flag, is being carefully restored to its 15th-century splendor.

In many respects, Old San Juan has a decidedly European flavor. The cobblestone streets of the seven-square-block city are a deep blue. The cobblestones were brought in as ballast on Spanish war ships, said an old man sitting under a shade tree outside Caletas de las Monjas, a 300-year-old former Carmelite convent that is now Old San Juan's only hotel, now called El Convento.

El Convento still retains all the charms of its past life. The 15-foot-tall mahogany doors lead to a huge foyer with tapestried walls and polished wood balconies. There are portraits of Spanish royalty and a chapel adjacent to the convent.

Old San Juan is also the cultural center of the island. Aside from the $100 million restoration of significant buildings like La Forteleza, the historic executive mansion, and the fortress El Morro, 400 other buildings are being restored.

The ride from the airport in San Juan to Dorado Beach, about an hour east, is a most sobering sight on your way to a quiet resort that is isolated but luxurious. The edge of the city of San Juan teems with shacks and other houses that look so primitive that one wonders if they have running water. But you also pass comely villas screened by palm trees and painted in a variety of pastels, and even in such vibrant hues as turquoise and hot pink.

Resort development continues on the island at a rapid pace, in spite of what's happening to the American economy.

Many new hotels have been built recently, many of them in relatively isolated sites on the island's coasts, including the Hyatt Regency Cerromar. The Cerromar is about an hour's drive from San Juan. Graceful swans float on an artificial river that runs through the tropical gardens built around the luxury hotel.

The Caribbean side of the island, which has developed at a slower pace than the Atlantic coast, recently has had a spurt of growth. One of the first developments on that side of the island was Palmas Del Mar, a vacation resort and a place where wealthy Puerto Ricans keep condominiums, renting them out during the high season.

Moonlight horseback rides, tennis lessons and sumptuous buffets are the order of the day at the hotel, whose rooms are free-standing bungalows set in a garden. You pass banana trees and other tropical plants as you go down winding stone paths to your room.

We took several side tips from the Cerromar. The biggest eye-opener was a morning spent exploring the depths of the Rio Camuy caves, site of one of the largest underground river systems in the world. One of the sinkholes at the caves measures 650 feet in diameter and is 350 feet deep.

A rare species of bat has lived in the caves for thousands of years and a species of shrimp peculiar to the caves lives in their dark pools. Tour guides ask visitors not to touch the walls of the caves so as to not upset the delicate ecological balance in any way.

A trolley carries visitors in a downward spiral from the mouth of the caves.