3. Stonehenge, UK
For centuries, archaeologists and historians have been intrigued by the prehistoric monument known as Stonehenge. Found in Wiltshire in Southern England, it includes a ring of about 100 huge standing stones. It is estimated that Neolithic builders needed roughly 1,500 years to construct it.
Each stone weighs about 25 tons. Each standing stone is around seven feet or 2.1meters wide and 4 meters or 13 feet tall The first bluestones are believed to have been raised sometime between 2400 and 2200 BC although they may have been there since 3000 BC.
