Cerro Tololo Inter-American Observatory is an NSF-supported mountaintop complex in northern Chile with more than forty telescopes and a long-running public programme. Free reserved tours depart by bus from the Route 41 observatory access gate every Saturday, visiting the SMARTS 1.5-metre telescope, the Víctor M. Blanco 4-metre telescope's observing room and platform gallery, and the site's Visitor Center room.