Mexico's archaeological treasury is vast, but two sites stand as global icons of pre-Columbian achievement.
Location: Yucatán Peninsula, 120 km east of Mérida.
Peak: 600–1200 CE (Terminal Classic to Early Postclassic).
Star attraction: El Castillo (Temple of Kukulkán) – 30 m step pyramid where the spring/autumn equinox creates a serpent shadow descending the balustrade.
Other highlights: Great Ball Court (largest in Mesoamerica, 168 m), Temple of the Warriors, Sacred Cenote (offering well), Observatory (El Caracol).
UNESCO: World Heritage since 1988; New7Wonders of the World (2007).
Location: 50 km NE of Mexico City, Valley of Mexico.
Peak: 100 BCE – 650 CE (Classic period).
Scale: 20+ km², population ~125,000–200,000 (6th largest city worldwide c. 450 CE).
Monuments: Pyramid of the Sun (65 m, 3rd largest globally), Pyramid of the Moon, Temple of the Feathered Serpent (Quetzalcóatl), Avenue of the Dead (4 km ceremonial axis).
Mystery: Builders unknown (pre-Aztec); Aztecs named it "where gods were born."
UNESCO: World Heritage since 1987.
Together, they bookend Mesoamerica's urban brilliance—Maya sophistication in the jungle, Teotihuacan's geometric order in the highlands.