Stone circles are ancient structures made of large stones arranged in a circular pattern. They can be found in various parts of the world, with some of the most famous examples located in Britain and Ireland. These circles are believed to have been used for ceremonial purposes, astronomical observations, or as burial sites. The exact reasons for their construction remain a mystery, but many archaeologists think they were significant to the communities that built them. Some stone circles, like Stonehenge, are aligned with celestial events, such as solstices, indicating their importance in early human understanding of time and the seasons.