A surprise awaits near Collinsville, 8 miles east of East St Louis: classified as a Unesco World Heritage Site with the likes of Stonehenge, the Acropolis and the Egyptian pyramids is Cahokia Mounds State Historic Site. Cahokia protects the remnants of North America's largest prehistoric city (20,000 people, with suburbs), dating from AD 1200. While the 65 earthen mounds, including the enormous Monk's Mound and the 'Woodhenge' sun calendar, are not overwhelmingly impressive in themselves, the whole site is worth seeing.
