The longest day of the year is 21 June or 22 June. It's the day when the sun is at its most nrtherly point and this is why it is "the longest day". In Wiltshire, there is a circle of huge stones at a place called Stonehenge, and hundreds of people go there to watch the sun rise on 21 June. These stones have stood for thousands of years and no one knows how they got there.
