WASHINGTON • The National Building Museum has had some pretty cool interactive exhibits over the past four summers.

There were two architect- designed mini-golf courses, a huge wooden maze and an indoor beach with an "ocean" of plastic balls.

You cannot help but think of cool, or possibly cold, at this year's installation, Icebergs.

The exhibit - an artful arrangement of large, white geometric structures, which opened last Saturday - was inspired by the designers' interest in climate change.

Mr James Corner, founder of landscape architecture firm James Corner Field Operations, said: "We feel quite passionately about issues surrounding the environment."

A double slide at the Icebergs exhibition (above), which was inspired by the designers' interest in climate change. PHOTO: WASHINGTON POST PHOTOS BY MARVIN JOSEPH

But the design team also understood the local climate.

"In July and August in Washington, D.C., it's super-hot outside, it's humid, it's sweltering," Mr Corner said at a preview last Thursday. "Wouldn't it be great to come into an environment that's literally cool?"

But you will not need a coat when exploring the giant structures, made from triangles of polycarbonate panelling, a material used to make greenhouses. The icebergs fill the museum's Great Hall, but Arctic temperatures are not part of the experience.

Visitors entering through walls of blue mesh and walking in and around the icebergs are supposed to feel as though they are underwater.

"What we're looking at at this level is the icebergs below sea level," Mr Corner said. "Nearly 75 per cent of an iceberg is below sea level."

The largest iceberg, which is 17m tall, contains stairs leading to a balcony with a view over the mesh. The peek from above is worth the climb and possibly a wait, given the small size of the balcony.

But the highlight for children is also inside the biggest berg: a double slide that is not particularly high but was quite slippery, according to young visitors.

"It's fast and fun," said Ben Smith, an eight-year-old from Washington who was exploring the exhibit with his family. He and sister Sarah made several test runs.

Ben, who had visited the other summer exhibits, said Icebergs did not have as much to do as The Beach did.

That was part of the plan, said Mr Brett Rodgers, head of communications at the museum.

Last year's installation "was an experience that invited sitting and playing with the balls", Mr Rodgers said. The more than 180,000 visitors often stayed several hours at The Beach.

"We want to get you... walking around the museum. Use your tickets to explore the other things that are in there," he said.

WASHINGTON POST

•The Icebergs exhibition is on at the National Building Museum till Sept 5. Go to www.nbm.org for details.