The longest day of the year, also known as the summer solstice, is Saturday, June 20.
The sun will rise at 4.43am and set at 9.21pm, giving us 16 hours and 38 minutes of daylight.
The summer solstice traditionally fell in between planting and harvesting crops, so people who worked on the land had more free time.
Around the northern hemisphere, many people gather to celebrate the summer solstice, or midsummer.
Why do people go to Stonehenge on the summer solstice?
For centuries people have held festivals, bonfires, picnics, Maypole dancing and other celebrations on the summer solstice.
Many people visit Stonehenge, the monument in Avebury Wiltshire that dates back to between 3,000 and 1,600 B.C, on the summer solstice.
Although people do not know why Stonehenge was built, it is a significant meeting spot for pagans.
Pagans have traditionally believed Midsummer’s eve to be the time when the veil between this world and the next is thinnest, and when fairies and mythical creatures were most powerful.
Last year, 10,000 people travelled to Stonehenge to celebrate the summer solstice.
What is the advice for today?
English Heritage has had to cancel this year’s Stonehenge event, because of the coronavirus pandemic.
On Saturday June 20, the sunset at Stonehenge will be livestreamed on the English Heritage social media platforms.
The next morning, the sunrise behind the Heel Stone, the ancient entrance to the Stonehenge Stone Circle, will also be livestreamed.
English Heritage has put together a programme of activities, including interviews with historians about the symbolism of the solstice.
Nichola Tasker, Stonehenge director at English Heritage, said: "We hope that our live stream offers an alternative opportunity for people near and far to connect with this spiritual place at such a special time of year and we look forward to welcoming everyone back next year.”
The Golowan Festival in Penzance, Cornwall, which celebrates the solstice, has also been cancelled – and a virtual festival will take place instead.
