Chankillo

Chankillo is a walled hilltop complex in the Casma desert with a line of thirteen stone towers running along a ridge below it, evenly spaced, forming a toothed horizon. From two observation points, one to the east and one to the west, the sun rises or sets in a different gap between towers on each day of the year, moving from one end of the line to the other and back between the solstices - which makes the line a solar calendar accurate to a day or two, in use from around 250 BC. That interpretation, published in 2007, established Chankillo as the earliest known solar observatory in the Americas, and UNESCO listed it in 2021. The rest of the complex includes a fortified hilltop building with concentric walls and restricted gateways, and administrative structures. It is in open desert with a visitor centre, and it gets far fewer visitors than its significance warrants.

What to look for

• The thirteen towers - a toothed line along a ridge marking the solar year.
• The observation points - the eastern and western stations the calendar is read from.
• The fortified hill - concentric walls and restricted entrances above the towers.
• The date - in use from around 250 BC, the oldest known observatory in the Americas.

When to go

Year-round; go early or late, both for heat and because low sun shows the alignments. Two to three hours including the walk between the towers and the observing points.

What to expect

Full desert conditions - intense sun, no natural shade, dust and wind. Walking between the towers and stations is over rough ground. The astronomy needs explaining to be visible; take a guide or read first. Facilities are limited.

Nearby

Sechín is near Casma; the coast and Chimbote are north.

Key facts