The huge burial mound of Maes Howe, circa 2500 BC, measures 115 feet in diameter and contains an enormous burial chamber. It was raided by Vikings in the 12th century, and Norse crusaders found shelter here, leaving a rich collection of runic inscriptions. Outside you see a large, grassy mound; the stunning interior of the chambered tomb has remarkably sophisticated stonework. This site is 6 miles northeast of Stromness and 1 mi from the Ring of Brodgar. Call early on the day of your visit to reserve a spot on the hourly tours.