6. Stonehenge
An abundance of tourists go to this well-known historical site each year. This ring was fashioned from massive stones around 4,000 years ago. Its size amazes everyone, and it’s unclear how ancient people managed to construct it without the use of modern technologies. Not a single scientist has been able to provide proof, despite several attempts to explain its intended application. Some believe it was a religious shrine, while others claim it was utilized for stargazing. However, no one can be certain.