(CNN) -- A waiter is making us fresh guacamole in a charming little restaurant in the heart of a Spanish colonial town. As I savor my first bite and think about my day exploring Mayan ruins and hidden underground worlds, I don't miss the beach at all.
A vacation to Mexico's Riviera Maya means one thing to most Americans: enjoying some of the most beautiful beaches in the world. But tourists who can tear themselves away for even a day will be rewarded with a glimpse at some of the Yucatan Peninsula's unique gems.
While vacationing in Playa del Carmen, my husband and I planned a day trip around a visit to one of the most popular Mayan ruins, Chichen Itza. The site is less than three hours by car from Playa del Carmen, and just over two hours from Tulum or Cancun.
Instead of taking an organized tour, we rented a car at our hotel for about $85 (U.S.) and got to Chichen Itza early enough to beat the crowds -- and the heat. Admission is about $10 each, and for less than $50 more, we hired a tour guide who spoke excellent English.
The massive pyramid, known as El Castillo, immediately draws our eyes as we enter the site. Recently named one of the New 7 Wonders of the World, it was built around 1000 AD and served as a temple to the Mayan god Kukulcan. Our guide shows us a neat acoustic trick -- he stands in front of one of the staircases and claps. The structure echoes back a chirping sound.
Throughout the ruins he tells us stories of ball games and ritual sacrifice and interprets hieroglyphics, pointing out the important symbolism of jaguars and snakes.
We are particularly struck by a building known as the Observatory, in an older section of the site. The remains of its circular tower are a memorial to Mayan interest in astronomy. After a little more than two hours we head to the exit, just as throngs of people are streaming in.
A descent into two cenotes -- sinkholes with underground pools of cool, clear water -- is next on our itinerary. We find Cenote Dzitnup after driving about 20 minutes in the direction of the town of Valladolid.
We pay $2 admission and climb down a narrow, slippery staircase into what feels like another world.
The water is bright blue, partially illuminated by sunlight seeping in from above. Stalactites and tree roots drip from the ceiling. Some children are swimming, their laughter echoing throughout the cave.
Cenote Samula is a short walk across the street. We find it even more otherworldly. A band of sunlight streams in through a large hole in the ceiling, where roots from a giant tree reach 100 feet or more to the water below. The cave is deserted except for a few snorkelers trolling through the water getting a closer look at some eyeless fish.
Valladolid, established in the 16th century by a Spanish conquistador, is just a short drive farther.
We park near the town's main plaza -- a square dotted with trees, benches and locals selling food and Mayan dresses. Lunch is long overdue, so we stop at a restaurant called El Meson del Marques. After an inexpensive meal of beer, guacamole, and some traditional Yucatan dishes, we are ready to explore the town.
In just a few blocks we descend into our third cenote of the day. Cenote Zaci is half open to the sky -- a good choice for the claustrophobic. A cutout in the stone ledge above the water is perfect for diving, and we witness a few brave souls taking the plunge.
We get a sense of the historical significance of the town a few blocks away, when we come upon a rustic yellow structure: the Church of Santa Ana. It was built for Mayan use in the 17th century and figured significantly into the Mayan uprising against the Spanish, which began in 1847.
Farther along the same road we find ourselves in the shadow of the towering Cathedral of San Gervasio. We peek inside as locals arrive for an evening service. A cathedral built on the site in the 16th century was so damaged in violence between the Mayans and the Spanish that it had to be torn down. The current building was erected in the early 18th century.
Finally we wander through one of the prettiest parts of town, called the Street of the Friars. Rows of colonial homes along the cobblestone street are painted in a variety of pastels and finished with neat white trim.
By now the sun has begun to set. In less than three hours, we are worlds away, back at our oceanfront resort. We have a late dinner, then get to bed. We need to rest up for another day of lying on the beach.