Aerial view of Stonehenge in Wiltshire, UK, with the low sun accentuating the circular henge and standing stones with long shadows. Stonehenge is one of the most famous prehistoric monuments in the world, it consists of a ring of standing stones, each around 4 metres high, 2.1 metres wide, and weighing around 23 tonnes. The construction of Stonehenge is believed to have started around 3000 BCE. Although its exact purpose remains a topic of debate, it is thought to have been used as a burial ground, an astronomical observatory, and a site for religious rituals and ceremonies. Today, Stonehenge is a UNESCO World Heritage Site.