This prehistoric site, the most famous in Great Britain, is a UNESCO World Heritage Site, and one whose significance continues to intrigue and raise questions for historians and visitors alike. It is thought that Stonehenge was built over several periods between 2950-1500 BC. Today, although a large number of the stones have collapsed or disappeared, from the centre of the circle it is still possible to watch the sun rise above the Heel Stone at the entrance during the summer solstice.