Between 400 and 650 AD, the Nazca people of what is now Peru dug a network of lines and figures in the earth covering a 50 mile distance. Some of these are geometrical patterns, while others are in the shapes of animals. While these can be seen from the surrounding hills, they are best viewed by air as Jackie Britton shows with an airplane flying over the 'hummingbird' formation. It is unclear what the purpose was, but one theory is that these were drawn to be seen by the gods in the sky. Another theory holds that these served as a type of astronomical observatory to help in the marking of certain rituals.