Explorers have discovered an astronomical “alarm clock” in South America that is as old as Stonehenge.
The find is an observatory that dates back 4,200 years and stands on top of a pyramid on a mountain peak in Peru.
It is the oldest such structure discovered in the Americas and is precisely aligned to the heavens.
The observatory marks the summer and winter solstices and was used by ancient man as a celestial calendar. By checking the movement of the stars over the seasons the locals knew when to plant their crops.
Scientists led by Robert Benfer of the University of Missouri say the observatory was built 3,000 years before the emergence of the Incas.
It shows that a sophisticated and scientifically aware civilisation existed in the region long before historians had realised.
Archaeologists are excited by artworks found at the site, called Buena Vista in a valley north of Lima, including a giant clay sculpture of a sad face, and drawings of a fox and a llama.
The treasures are remarkably well preserved because the region only gets around one day of rain a year.
Experts say the pyramid observatory was used 2,200 years BC, 400 years after the first pyramid was built in Egypt.
Other ruins at the Buena Vista site date back 10,000 years, they discovered.
Archaeologists believe Stonehenge in Wilshire was built between 4,000 and 4,500 years ago and that it may also have been used as an astronomical calculator.