Sewell, the "city of the stairs", clings to the side of the Andes at 2,200 metres about 60 km east of Rancagua. Built from 1905 by the American copper company that opened El Teniente, it is a planned town with no roads — all streets are stairs, all houses are painted bright primary colours, and the layout follows the contours of the mountain. UNESCO World Heritage since 2006.
The only way to visit is on a guided day trip from Rancagua, run by VTS Tours and a few competitors who hold the licence. Most include a brief look at the mining museum, a walk through several restored streets, and lunch. Pre-booking is essential — Sewell sits inside the operating El Teniente mine concession, and access is controlled. Tours run year-round but winter snow can close the road for days at a time.