Earthworks

3 ancient earthworks across 2 countries, from Goseck Circle (4,900 BCE) to Cahokia Mounds (1050 CE), and the theories that connect them.

c. 4900 BCE · Germany

Goseck Circle

One of the oldest known solar observatories on Earth — seven thousand years old, rebuilt in timber.

c. 300 BCE or 1070 CE (contested) · Ohio, USA

Serpent Mound

A 400-metre serpent uncoils along a ridge above a crater, swallowing an egg of sun.

c. 1050–1350 CE · Illinois, USA

Cahokia Mounds

A pre-Columbian city larger than the London of its day, built entirely of earth.