stonehenge
Ancient rock formation is believed to be 5,000 years old -- but no one is sure what it was used for.
Artifacts found near the mysterious monument show evidence of feasting on beef and pork.
"Could the builders of Stonehenge have visited Mars... or is this just another face on Mars illusion?"
"Everything written previously about the Stonehenge landscape and the ancient monuments within it will need to be re-written."
