Festival-goers will attempt to create the biggest human peace sign - as temperatures return to normal at Glastonbury.
Dozens of people were treated by paramedics at the 900-acre site in Somerset on Wednesday on the hottest day in the event's history.
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People sought shade in bushes and donned bikinis rather than wellies as temperatures hit 31C (87.8F) on the first day at Worthy Farm in Pilton.
Staff sprayed people with water, handed out free sun cream and hats, and urged them not to drink alcohol while queuing to enter the site.
Temperatures began cooling in the late evening and by Thursday morning were at 17C (626F) with cloudy skies, in line with previous years.
Thousands of people are expected to gather in the Stone Circle in Kings Meadow at 12pm to send a "message of peace to the world".
They will attempt to create the biggest peace sign, beating the current record of 5,814 participants.
Beth Llewellyn, organiser of the Peace Garden in the Green Fields, is behind the record attempt - which comes after terror attacks in London and Manchester.
She said: "I thought 'Why don't we get together in the fields, and make this sign around the Stone Circle with people whose intent is for peace and not to be threatened by the few?'
"We're just doing it for love. I'm really looking forward to it."
Before Wednesday, the hottest days at the Glastonbury Festival had been in 2010 and 1989, when temperatures reached 27.3C (81.1F).
South Western Ambulance Service had treated 38 people for a "range of incidents" including those related to heat by 2.30pm on Wednesday.
Security at the festival, which will host a population of 200,000, is tighter than previous years following the recent terror attacks.
Police dogs searched bags for explosives and illegal substances as people entered to site.
The festival is being headlined by Radiohead, Foo Fighters and Ed Sheeran.
Hollywood star Johnny Depp will make an appearance, while Labour leader Jeremy Corbyn is due to give a talk and introduce US rap duo Run The Jewels.