The Stones of Stenness is a prehistoric monument located on the mainland of Orkney, Scotland. It consists of a circle of 12 standing stones, with the tallest measuring about 5.6 meters (18 feet) in height. The circle is about 32 meters (104 feet) in diameter, and is surrounded by a ditch and bank.

The stones were erected during the Neolithic period, between 3000 and 2000 BCE, and are thought to have had religious or ceremonial significance. The exact purpose of the monument is not known, but it is believed to have been used for rituals and possibly for astronomical observations.

The Stones of Stenness are part of a larger complex of ancient monuments in Orkney, which also includes the nearby Ring of Brodgar and the Maeshowe chambered tomb. These sites are collectively known as the Heart of Neolithic Orkney and were designated as a UNESCO World Heritage Site in 1999.

The Stones of Stenness have undergone some damage and alteration over the years, with some stones being broken or removed, and others being repositioned. However, the circle remains an impressive and intriguing monument, and continues to attract visitors interested in the history and mysteries of the ancient world.