Mayan Ruins Chichen Itza: Mighty Chichen Itza is one of the largest and best maintained sites in Mexico. It is actually two cities: one that was ruled by the Mayans during the sixth to the tenth century; the other a Toltec-Mayan city that emerged around the year 1000 a.d. Most of the prominent building were developed during the city's "rebirth" under Toltec rule. The towering Castillo displays a mixture of Toltec and Mayan influences, and is fraught with cosmological symbolism. Its four sides contain 365 steps (depicting the solar year), 52 panels (for each year in the Mayan century), and 18 terraces (for the eighteen months in the religious year). There is an interesting temple inside the Castillo, accessible via a narrow stairway. The enormous ball court is the largest every discovered, and is lined with fascinating carvings. The site also contain a cenote, or sacred well, an Observatory, the imposing Temple of Warriors, and the Nunnery, along with dozens of other structures. Count on spending at least an entire day here. During the Fall and Spring Equinox (March and September) the sun's shadow forms an enormous serpents body on the face of the pyramid known as "El Castillo." English guided tours are available. A full day excursion to Chichen Itza costs around $50 US per person. Tulum: This modest-sized coastal city is one of the loveliest archaeological sites in Mexico. It is a popular day excursion from Cancun. It is the only Mayan port city ever discovered, and one of the few to still be occupied when the Spaniards arrived in the 16th century. Overlooking the turquoise Caribbean Sea, Tulum is a gleaming-white walled city that invites visitors to roam its small temples and buildings. The site exhibits strong Toltec-Mayan influences. The Temple of the Frescoes contains faded interior wall murals, and the Temple of the Descending God portrays a god tumbling from the heavens. This is a major destination for tour buses, and is best explored later in the afternoon, when the masses have departed. Admission is collected, and several English-speaking guides are available for hire. Coba: Approximately 3 hours drive from Cancun, this once-great city (now being extensively studied for the first time) is a jungle-bound site measuring in all some 50 square kilometers in size! The site thrived between 500-900 a.d. before being abandoned and swallowed by the ever encroaching jungle. Much of the site is still unexcavated, giving visitors an eerie, "Indiana Jones" experience. It is surrounded by dense jungle and five freshwater lakes (some of the only lakes in the entire Yucatan region). Excavation has unearthed Nochuc Mul, a 138- foot tall Pyramid (tallest in the Yucatan), a nine-tiered castle, and a ball court. The site has more sacbe (wide limestone-paved ancient roads) than any site yet discovered.