El Castillo, the pyramid at Chichen Itza. — Photo courtesy of Celso Flores

If you only have time to go on one sightseeing excursion while vacationing in Cancun, visit the Mayan ruins of Chichen Itza. The ruins are a UNESCO World Heritage Site and, in 2007, this major archaeological site was named one of the New Seven Wonders of the World. It is the most popular attraction in the area and should not be missed.    

The ancient city, believed to have once been the religious center of the region, was built over 1,000 years ago. When you see the size of the place, the details in the stone carvings, and the shear size of the well-preserved pyramid & other buildings, you'll wonder how the Mayan people fabricated such impressive structures, using only primitive tools.

The Mayans were incredibly advanced in the areas of astronomy and mathematics and they had a very "sophisticated written language". The concept of the number zero was included in the Mayan numerical system. The entire site of Chichen Itza is believed to have been built in alignment with the stars. Today, historians and archaeologists are still mystified by the Mayans' understanding of math, astronomy, and by how the existence of the planets was even known to them, so long ago.

The Kukulkan Pyramid, also known as El Castillo (the castle), is the name of the iconic pyramid that is the main focal point of the park. The 365 stairs, that lead to the top of the pyramid, signify the number of days in one year.

Each year, during the vernal equinox and the autumnal equinox, large crowds gather at the base of El Castillo, to watch what appears to be a snake slithering down the stairs. This phenomenon occurs as the sun sets.  

As the sun sinks lower and lower, the shadows appear to move down the stairs, like a snake crawling down stairs, until the shadows align with serpent heads that are at the bottom of the pyramid's staircase. Scholars believe this event had some agricultural significance to the Mayans and that, perhaps, it signaled that it was time to plant crops.   

When you arrive at the park, you have several options for touring the site. You can hire a guide to take you on a tour of the ruins, you can rent headphones and a recorded tour so you can take a self-guided tour, or you can simply see the park on your own, without any form of guidance.

To see Chichen Itza, you can book either a group tour (bus tour) or a private tour. Group tours are usually less expensive than private tours, but private tours allow you to set your own schedule. If you schedule an early pick-up time for your private tour to Chichen Itza, you will get to the park and begin exploring the ruins before the tour buses start to arrive. 

Another benefit of booking a private tour is that you can combine your visit to Chichen Itza with stops at other nearby sites and attractions. Ek Balam, a recently discovered site of Mayan ruins, and the quaint colonial town of Valladolid are both nice options to add on to a tour to Chichen Itza. Stopping for a swim in one of the many cenotes (sink holes) in the area is another fun way to extend your tour.