Avebury is a megalitic stone circle near Stonehenge, but older and more complex.It's so big there's a village inside!
Stonehenge is the most famous prehistoric monument on Earth.It's now a world heritage site.
What was this vast collection of stones intended for? Was it an observatory of the moon, a temple to the sun or a cementery?
Nobody knows. But there is something everybody knows: it's a wonderful work of engeneering and design.