The Serpentine Gallery's summer pavilion, designed by world-renowned French architect Jean Nouvel, has been unveiled.
The huge red geometric structure is the 10th commission in the London gallery's annual architectural series.
It is filled with objects intended for games and leisure, including chess sets, picnic blankets and frisbees.
The pavilion, which is open to the public until 17 October, is Nouvel's first completed building in the UK.
His designs are behind more than 200 buildings around the world, including Copenhagen Concert Hall, the Arab World Institute in Paris and Lyon Opera House.
Launching the pavilion, Nouvel said: "When I see the red sun through the ceiling I am happy."
He said the effect of the light shining through the work made it resemble stained glass.
"The red for me was the idea of something very strong, energetic and optimistic and also complementary because the green, you can see that around," he added.
The pavilion commission was conceived in 2000 and each year the gallery hosts an experimental structure by an accomplished designer who has six months to complete the project.
Hundreds of thousands of visitors flock to see the pavilions each summer.
Previous commissions include last year's "floating pool of water" created by Kazuyo Sejima and Ryue Nishizawa of Japanese architecture firm Sanaa.
In 2008, architect Frank Gehry created a glass and wood structure, partly inspired by Leonardo Da Vinci.