Located in Wiltshire, UK, Stonehenge is a series of massive stones arranged in circles with estimated age 3100 year BC. The Stonehenge was constructed in three phases and apparently took nearly 1,500 years to build (completed in 1600BC). Some huge stones in Stonehenge weigh more than 65 tones and believe to be excavated nearly 200 miles away from construction site (from Preseli Hills in Wales). With all these efforts and sophisticated work, there is no any evidence found on the construction site of Stonehenge about the purpose and process of its creation, baffling the scientist and archeologist for centuries.
Ancient alien or ancient astronaut theorist considering that early Neolithic civilizations was assisted by extraterrestrial beings who arrived on Earth thousands of years ago and have superior knowledge of science and engineering. The reason behind the Stonehenge creation is as propose by ancient alien theorist, is it served as a landing pad for aliens spacecrafts