Hito al Trópico de Capricornio, Memorial in Antofagasta, Chile

The Hito al Trópico de Capricornio is a memorial in the Atacama Desert north of Antofagasta that marks the Tropic of Capricorn. Its main feature is a copper-clad steel arch standing 10.4 meters high, flanked by two 12.4-meter-tall walls that form the Sun Gates.

The Rotary Club of Antofagasta conceived and funded the monument, and architect Eleonora Román designed it using astronomical calculations by science writer Jorge Ianiszewski. It was inaugurated on 21 December 2000, the southern summer solstice, at the moment the site passed directly under the Sun and vertical objects cast no shadow. Chile's Dirección de Vialidad had fixed the exact tropic line by GPS.

The monument was devised and funded by the Rotary Club of Antofagasta, and its name refers to the Tropic of Capricorn, the latitude it marks. Its design by architect Eleonora Román drew on astronomical calculations by science communicator Jorge Ianiszewski, who conceived it as a solar calendar. The upper edge of the Capricorn Arch casts a shadow along the Path of the Sun that marks the seasons.

The monument stands 28 km north of Antofagasta beside Route 1, the coastal highway, near the Andrés Sabella airport and the Cerro Moreno air base. Access is by road; the ground around the 30 m Circle of the World is flat desert, so you can walk between the arch, the Sun Path and the Sun Gates. The site lies in open terrain with no shade.

The Circle of the World is a 30-metre-diameter ring framing the monument as a model of the Earth, with the Tropic of Capricorn line set 23.44 degrees from the line standing for the Equator. The upper edge of the 10.4-metre Capricorn Arch casts its shadow along the 11.1-metre Sun Path to mark the seasons.