More than 5000 years ago Europeans were building spectacular stone monuments. Many of these are still standing today, as mysterious relics of a long gone society.
These enormous stones are called megaliths, which literally means big stones.
Some were set up on their own, others in groups or in circles. Some megaliths marked the burial place of an important ruler, while others seem to have religious meaning.
Tall single stones are called menhirs. Stone slab-tombs are called dolmens. The remains of large circles of stones and wooden posts are called hanges.
Menhirs, dolmens and henges are still standing today.
Stonehenge is an example of remainders from the Megalithic era.
Stonehenge is a complicated structure on the outside of which is a circular ditch, with an entrance gap.
Stonehenge was built in stages between 1800 and 1400 BC.
During the second stage of building, blue stones from the Preseli mountains in Wales were hauled onto the site in an astonishing feat of organization and transport.
Local stones were added in the third stage and were up to 10 metres long and weighed 50 tonnes.
The Stonehenge builders had only stone or bronze tools to work with. They had no machines and yet they tackled huge digging works.
They buried their chieftains with treasures and food for the next world, beneath mounds of Earth they called barrows.