Archaeologists using revolutionary airborne laser technology have discovered a lost mediaeval city that thrived on a mist-shrouded Cambodian mountain 1200 years ago.

The stunning discovery of the city, Mahendraparvata, includes temples hidden by jungle for centuries – temples that archaeologists believe have never been looted.

An instrument called Lidar strapped to a helicopter criss-crossed the mountain's topography and revealed an web of canals, dykes and roads connecting two dozen temples — the city that founded the Angkor Empire in 802 AD.

(WATCH the video below or READ the story w/ lush photographs from the Sydney Morning Herald)