El Caribe Mexico.

Is kicking back on a sandy beach your idea of a vacation gateway? Perhaps you prefer hobnobbing with inhabitants of the underwater world? Maybe exploring the ruins of ancient civilizations is more your speed? Or does the action of a busting and exotic tourist resort sound appealing? You'll find all that and more on the eastern seaboard of Mexico.

The northern and western coasts of the Yucatan Peninsula jut into the Gulf of Mexico, but its eastern border lies along the crystal clear, turquoise-blue waters of the Caribbean Sea. On the Caribbean side of Mexico, the beachfront resort cities of Cancun and Cozumel are the most popular tourist destinations. And, Mexico's rich archaeological and aquatic treasures can easily be found nearby.

FASHIONABLE CANCUN

It's hard to imagine that less than 20 years ago Cancun was a virtually uninhabited, uncleared stretch of land. Its "discovery" was made by computer when the Mexican government, buoyed by the success of Acapulco, was searching for a new location to build the ideal vacation spot from scratch. Officials fed the attributes of several locations into the computer and Cancun won hands down.

A 14-mile-long islet shaped like the numeral 7, Cancun island, which comprises Cancun, is only one-third of a mile across at its widest point. But that is wide enough to accommodate dozens of beachfront hotels, restaurants, and marinas, and night spots--that range from jazz and reggae clubs to discos.

On each end of this "hotel zone" is a bridge that connects the islet to Cancun Centro, the bustling downtown area. Not only will you find more places to shop and eat there, but you also get a sense of the daily life of the island's permanent residents.

It's a given that while in Cancun you'll want to spend a great deal of time on the beach. Even non-swimmers delight in the crystalline, perfectly blue water and the white, limestone, "air-conditioned" sand that stays cool even on the hottest days.

All of Mexico's beaches are public, including those where luxury hotels are located. For water babies, opportunities abound for swimming, snorkeling, scuba diving, windsurfing and water=skiing. As a precaution, tourists should ask their travel agent about the depth and temperament of the water near certain hotels. Some areas have a dangerous undertow; others offer calmer waters, but may be too shallow for swimming without going farther away from shore. Punta Cancun, the area near the Hyatt Regency and Camino Real hotels, is said to offer some of the best water for swimming.

Golfers will enjoy spending time at the 18-hole Pok-Ta-Pok Golf Club, often referred to as the Robert Trent Jones Golf Course. there is even a Mayan ruin on the 12th hole of the course, which was discovered during the club's construction.

Since Cancun was built from the ground up and opened in 1974, you will find little--except perhaps the people themselves--that provides a sense of Mexico's rich history. To get a taste of Mexican traditions, take in a floor show at one of the hotels or restaurants, such as the dinner show at the Cortijo Flamingo, where the Ballet Folklorico Nacional performs Monday through Saturday. A champagne cruise on the Fiesta Maya features not only a luscious buffet dinner and romantic moonlit view of Cancun's lagoons, but a high-energy Latin Festival show.

On Wednesday afternoons, take in a bullfight, if you are so inclined. And, for a tiny taste of Mayan civilization, head for the Museo Arqueologico de Cancun, or visit the ruins at El Rey.

Quiet Cozumel

For those who prefer a more authentic Mexican ambience, try Cozumel. A bit more laid back than its ultramodern neighbor, Cozumel is a popular vacation spot that offers all of the amenities you could want, without giving you the feeling that it's teeming with tourists.

The natural underwater park and botanical garden of Parque Chankanaab is a must see. Here snorkelers and scuba divers can explore fascinating caves and even a few sunken ships. The best scuba diving spot, however, is Palancar Reef. Ranked as one of the best diving sites in the world, it is also known for its rare black coral. Those who are a bit water shy can visit the Museo de Cozumel in San Miguel, the island's only town. The museum features three-dimensional cave models, a permanent ethnographic and historical exhibits, plus special exhibitions. For those who simply want to have a good time on the beach, head for San Francisco Beach, a popular hangout on the southwestern end of the island.

Cozumel also has a few Mayan archaeological sites, but they won't measure up to what you can see in Tulum or Chichen Itza. Archaeological sites closer to Cozumel are nearby El Castillo Real and San Gervasio. But most tourists find the journey to the sites more exciting than the destination. On both trips you will see masses of lush vegetation and colorful wildlife, but its bumpy roads are best traveled in a four-wheel drive vehicle.

Quaint Isla Mujeres

Take a trip to nearby Isla Mujeres, a quaint fishing village complete with cobblestoned streets and wooden houses. There are plenty of opportunities for shopping, and you'll find good bargains on silver jewelry.

Snorkelers and scuba divers get an eyeful at El Garrafon, the island's national park. You can even have your picture taken while you wrestle a sand shark--the folks back home don't have to know that this is a friendly species.

Archaeological Treasures

Conventional lore says that Chichen Itza was conquered by the Toltecs--another Mexican civilization--in A.D. 987. but that theory remains in dispute even today. What is clear, however, is that Chichen Itza is a blend of Mayan and Toltec culture. The archaeological remains there offer an overwhelming look at an ancient people who enjoyed a complex social organization and a well-developed scientific and mathematical intellect.

Chichen Itza, which spans seven square miles, also boasts the famous 75-foot El Castillo pyramid, built apparently with the Mayan calendar in mind. The pyramid's 364 stairs and the platform at its summit represent the days of the year. Its 52 panels are said to correspond with the 52-year cycle of the Mayan calendar. And its 18 terraces are said to represent the mayan 18-month solar calendar. Another site is the Main Ball Court, which is more than one-and-one-half times the size of a modern football field. The game that was played here seems to have been a cross between basketball and soccer.

El Caracol, an observatory in Chichen Itza, speaks to the Mayan's astronomical genius. From here, astronomers could chart the approach of the spring and autumn equinoxes and the summer solstice.

Rather than making Chichen Itza a one-day excursion, make it an overnight stay. There is much to see and the site is a 125-mile drive from Cancun. That means, if you leave Cancun or Cozumel in the early morning, you're likely to be climbing these vast pyramids during the hottest part of the day. The best way to see Chichen Itza is to stake out a hotel as soon as you arrive or make reservations beforehand (see sidebar). Get your first taste of the ruins, then as the day grows hot, take a lunch break and siesta. Make your second visit to the ruins as the day begins to cool.

The ruins at Tulum are not nearly as impressive as those of Chichen Itza, but its setting--a 40-foot cliff overlooking the sparkling Caribbean Sea--is spectacular. There is some dispute whether the wall that surrounds Tulum on three sides serves as evidence that the city was once a walled fortress designed to keep out pirates, or simply a divider used to distinguish ceremonial buildings from the surrounding residences. There are 60 structures to view, with murals and carvings that reveal the Mayan people's deep spirituality.

The ruins at Tulum and Chichen Itza are both worth the trip, but if time is a concern and you must choose between the two, consider these factors. The structures at Chichen Itza are the most impressive, but Tulum is only 78 miles from Cancun and can be toured in just two or three hours. You'll need twice that amount of time to see Chichen Itza, and it will take much longer to get there.

If you are taking a day trip to Tulum, it should include a visit to the Xel-ha (pronounced, Shellhah) National Park, the world's largest natural aquarium. forget about troubled waters here; this network of calm, clear lagoons offers delightful swimming.

Whether you plan every minute detail of your vacation before you travel, or leave some of your plans open, a trip to the Mexican Caribbean is the place for a perfect holiday. You have so many options that you can never be left idle--unless, of course, that is your preference.