The granite boulder weighs more than 60 pounds (28 kilograms) and is a little less than a foot (30 centimeters) across. It was discovered in a niche in the back wall of the chamber and was the ...

researchers at ETH Zurich have let an autonomous excavator loose on a big pile of boulders and reclaimed concrete. The goal? To build a 20 foot (6 meter) and 213 ft (65 m) long dry-stone wall as ...