Unlike its predecessors, the Hart Building boasted a contemporary, energy-efficient design that could accommodate a growing number of staff members and various technological innovations.

While the building was under construction, a panel of curators was charged with identifying potential sculptors and establishing criteria for the commission of a contemporary work to enliven the atrium.

On November 10, 1976, Calder brought the Mountains and Clouds maquette—his 20-inch (510 mm) sheet-metal model—to Washington, D.C., to present it to the Architect of the Capitol and finalize the placement of the piece.

But in 1979, fabrication was delayed and nearly terminated when public funds for the sculpture were eliminated from the costly construction budget for the Hart Building.

Financial assistance materialized in 1982 through Senator Nicholas F. Brady, who believed the Calder sculpture to be "the right work for the right place at the right time."

[2] On its website, the Architect of the Capitol explains: “Since the structural safety analysis identified the clouds as unsafe for reinstallation due to significant structural defects, the Architect of the Capitol, in consultation with the Calder Foundation, has determined that the best course of action is to refabricate the clouds to the artist’s original intent.” [3] Because the interior of the atrium presents a complex background of doors, windows, balconies and stairwells capped by a coffered ceiling, Calder stressed simplicity in the design of the sculpture.

As one passes through a low lobby, only a section of the black steel sheets of the mountains appears, perceived as a virtually flat surface.

But by locating the nearest portion of the stabile some 40 feet (12 m) from the atrium's east wall, Calder allowed viewers the necessary space and distance to take in the whole work.

The work presents an open, more fully readable composition of two or three peaks with legs and clouds that seem to float in front of the mountains.