Among the notable sights there are the Observatorio (Observatory), also known as the Caracol, the Juego de Pelota (Ball Court) and the Piramide de Kukulcan (Pyramid of Kukulcan), where you can witness the shadow image of a plumed serpent descend on the pyramid’s stairs every spring equinox.

CHICHEN ITZA
Thanks for your vote. Chichén Itzá, one of the new 7 wonders of the World.
The ancient Mayan capital of Chichen Itza is an archaeological zone in the eastern region of the state of Yucatan. It lies 74 mi (120 km) east of Merida and the climate is hot and dry, with an average temperature of 93º F (34 C).

This place, declared a World Heritage Site by the UNESCO, will take you back in time to the pre-Hispanic era as you discover the secrets awaiting you in the most important structures. At El Castillo (also known as the Pyramid of Kukulcan), a natural phenomenon occurs each year during the spring equinox: the sunlight creates a shadow image of a plumed serpent descending down the pyramid’s stairs. This unique experience draws hundreds of tourists from all over the world. Another important structure is the Juego de Pelota, the largest ball court in Mesoamerica. There’s also the Observatorio (Observatory), or Caracol (Snail), called that because of the interior’s round spiral shape.

At Chichen Itza you can also visit the spectacular Cenote Sagrado, a large sinkhole that measures 198 feet (60m) in diameter. Many fantastic treasures have been found at the sinkhole: rings, necklaces, gold and jade objects, as well as the bones of young women that were thrown into the water as an offering to Chaac, the Mayan rain god. Chichen Itza is an ideal destination, not only for those who enjoy archaeology, but also for those who like history and the charming allure of ancient civilizations

ECOTOURISM
Along the Mayan Riviera you will discover a wide variety of ecotourism options, allowing you to admire the spectacular wildlife at the main ecological reserves. You can also participate in projects to protect endangered species, such as marine turtles. The experience will put you in direct contact with nature, making it all the more enjoyable. 
Ecotourism outings include Celestun, the natural habitat for hundreds of pink flamingoes, or Ria Lagartos, where you can go kayaking through the mangroves. At Playa del Carmen, the Mayan Riviera’s cosmopolitan city, you’ll find excellent tourist facilities at ecotourism parks Xcaret and Xel-Ha, ancient Mayan ports that have been converted into modern-day paradises.  Also nearby are numerous sinkholes where you can do rappelling and cave diving while exploring the amazing depths of underground river systems.

Xcaret is located 8 km (5 mi) south of Playa del Carmen; this ecological park offers attractions you won’t find elsewhere, such as the archaeological ruins of one of the most important ceremonial centers of the Mayan culture. Its natural beauty is one of a kind and benefits from ponds, caves, underground rivers full of colorful fish, and a reef aquarium. This park’s archaeological design allows visitors to admire the platforms and buildings of a ceremonial center, like such structures as the Caracol, the Main Temple, the miniature temples and the residential areas

XEL-HA is located in the heart of the Riviera Maya in Mexico's state of Quintana Roo, 122 kilometers/76 miles south of Cancun and only 13 kilometers / 8 miles from Tulum. The park is open year-round and has the most spectacular natural aquarium of the world for you to experience all kinds of aquatic adventure. Explore this theme park and enjoy natural, ecological attractions and water activities like diving or snorkeling in creeks, lagoons, natural wells and ancient caves fed by subterranean rivers flowing to the beautiful Mexican Caribbean Sea of the Riviera Maya.  Also, Swim with dolphins in the paradise! Xel-Ha offers phenomenal programs with their resident 6 Dolphins and all the activities surrounding Dolphin World are truly unforgettable and are definitely experiences you don't want to miss. Xel-Ha has taken special care and dedication in the design of the natural reserve's dolphinaria by providing the dolphins an environment much like their own, making the dolphins feel more at home.

SCUBA DIVING
For several decades now the Mayan Riviera and Cozumel has been considered an ideal place to scuba dive, thanks to its biodiversity of marine life. In its waters you can see countless schools of angelfish and parrotfish, as well as sponges and manta rays that inhabit the Great Mayan Reef. The reef system is the second largest in the world, spanning from Isla Mujeres to Costa Rica. In Cozumel’s National Reef Marine Park you’ll find 25 reefs where you can scuba dive, some of which are excellent spots for novice divers due to the calm waters.

Playa del Carmen has many marvelous spots to go snorkeling, scuba diving and even cave diving. Along the Great Mayan Reef, the second largest coral reef system in the world, you can dive among hundreds of multicolored fish and discover coral formations that have been around for more than 500 years. At the sinkholes (ponds connected to underground river systems) located in Playa del Carmen’s environs you can explore various caves and caverns full of stalactite and stalagmite formations, allowing you to take in sights of rare beauty that few people will have the opportunity to see.