Close your eyes. Think of warm, sunny days with puffy, white clouds. Imagine a soothing sea breeze rustling through statuesque palm trees. Picture coconut-oiled tourists baking in a tropical sun on wide, sandy beaches.

This is not Miami Beach, Cancun or Cape May. This is Puerto Vallarta.

Puerto Vallarta is not your grandfather's Mexico. It is a vibrant, pulsating, first-class resort snuggled adjacent to an old Mexican fishing village. The Mexican Riviera hugs the Pacific coast from quaint Mazatlan to the new, underdeveloped and emerging Huatulco. But it is Puerto Vallarta that seems to mix the old with the new rather spectacularly.

My enchantment with Puerto Vallarta started in 1971, with spring-break stories recounted by a graduate-school friend. Twenty-three years later, I journeyed there to see what all the fuss was about. I was not disappointed. It was there that I had one of the most memorable experiences of all my travels.

South of Puerto Vallarta is Yelapa, an isolated fishing village. This is truly a land that time has forgotten. There are no roads, and the only way to get there is by boat. I chose the 40-foot, double-decker Buenventura with some newfound friends. The trip was rather bumpy as we chopped our way down the coast.

The first stop was Los Archos, a delightful snorkeling spot. The water was crystal clear, and the fish were large and friendly. A nourishing local chicken dish was served at Las Animas Beach.

For the non-adventurous, there was a wide, clean beach to enjoy. But I had not come all this way for the beach - I was looking for the thrill of a lifetime.

Not far from the palapa-roofed beach restaurants, guides offered tours for courageous horseback riders. For a nominal, negotiable fee, you could rent a horse to ride up the side of the mountain through Yelapa, which clings precariously to the mountainside, lest it fall into the sea.

Yelapa is an area of untouched splendor. The mountains flow to the sea, and the dense jungle hugs the mountainside. You ride a full-sized horse to Quimoto along a trail no wider than the horse. The trail wanders through a town, where your courage is cheered by children and dogs.

The ride slowly traverses switchbacks meandering up the mountainside, with the foaming surf a sheer drop below. The horses make the trip twice a day, five days a week, and they know exactly where they are stepping, but they can feel and sense fear. I watched a timid teenager have to conquer her own demon fear, because she could not rely on her mother to soothe the beast she was riding.

Finally, you reach the top and ride into a jungle valley to find the waterfall of Quimoto. The terrifying ride was worth it, as you are cooled by the spray of a cold mountain spring. Adventurous souls can swim in the picturesque lagoon. The cares of the modern world never invade this delightful spot.

As a group, we sat and enjoyed the silence of nature and soaked up the beauty of the moment.

Nobody was the same on the ride back. Each of us had conquered some of our demons and absolutely trusted the horses to keep us safe.

James H. Robertson lives in Jenkintown, Montgomery County.