Outside, D.C.’s notorious 90-degree average highs make the the nation’s capital feel like it’s melting. A recent architectural intervention at the National Building Museum, however, offers a rock-solid respite from the heat.

In July, New York landscape architects James Corner Field Operations unveiled “Icebergs,” an immersive installation that transforms the soaring atrium of the museum’s Great Hall into a chilly oasis. A rectangular blue mesh enclosure hangs from the 75-foot-tall ceiling, inside of which visitors take on the role of underwater voyager, navigating a blue abyss filled with clusters of hyper-geometric icebergs (and children). Some freestanding forms rise from the floor like mountains, while some, suspended like stalactites, pierce through the fabric ceiling. The tetrahedral structures are simple translucent polycarbonate on frames of 2’x2’ wood, which will offer pain-free disassembly when the installation comes down on September 5.

Corner composed an underwater landscape that unfolds in a narrative arc that climaxes once you've dodged the dense field of icebergs. The space clears and a singular grand cluster hangs overhead like chandelier. The open floor is littered with white beanbags, including a few hidden behind little iceberg nooks, on which to recline and ponder the ceiling (comprised of both the suspended icebergs, and the 19th-century museum’s Corinthian columns). The mesh tints the museum beyond the seascape blue, and serenely reflects the portico-shaped light streaming in from the upper floors.

For the kiddies, one iceberg houses a Japanese snow cone stand, while the inner scaffolds of another lead to a pair of slides, and then, a few levels further up, a narrow viewing platform that emerges above the mesh enclosure. From above, either on the viewing platform or from the arched corridors of the museum’s upper floors, the mesh takes on greater opacity, and the tips of the icebergs look like icy pyramids floating on a calm sea.

For the museum, it’s an interactive lesson in structural geometry, science, and a subtle warning of the beauty we stand to lose to global warming, but for most visitors, an ambient space to sit and chill.

“Icebergs” is on view at the National Building Museum through September 5.