How Collectors Jon and Kim Shirley Stepped In to Restore the Senate Building’s Famed Calder

In March 2016, former president and chief executive of Microsoft Jon Shirley and his wife, Kim, flew from Seattle, where they are based, to Washington, D.C., for a meeting of the National Gallery of Art’s Collectors Committee. While in town, they visited Alexander Calder’s monumental sculpture Mountains and Clouds (1976/1986), in the atrium of the Hart Senate Office Building. Longtime collectors of Calder’s work—three years ago they donated 48 works, valued at $200 million, from their Calder holdings to the Seattle Art Museum—the Shirleys did not like what they saw. The mountains—the stabile part of the sculpture, standing 50 feet high—were there. But the four clouds, a mobile meant to hang from the 90-foot-high ceiling, were missing.

“It was surprising and dismaying,” Jon Shirley told ARTnews this past summer. After an earthquake, the clouds had been taken down for analysis and then determined unsafe for reinstallation due to structural defects. The Shirleys decided, then and there, that they would spend whatever it took to get them back in place. Ten years and $10 million later, their efforts are about to bear fruit.

Massive, black, and imposing, Mountains and Clouds is Calder’s final work and the only one of his pieces to combine a separate mobile and stabile. Inclusive of the clouds—the largest of which is over 40 feet long and weighs nearly one ton—it’s the largest work of modern public art in the nation’s capital, second in size only to the Washington Monument. “It’s one of the most powerful artistic expressions in the nation’s capital, and a landmark achievement of American public art,” Shirley said.

Calder’s design was selected in 1975 by the architects of both the Capitol and Hart buildings, and approved by Senator Philip Hart (Democrat of Michigan), for whom the building was named. Calder came to Washington in 1976 to approve the maquette; the next day, back in New York, he died. Three years later, during cost-cutting on the building’s construction, funds for the sculpture got slashed, so New Jersey Senator Nicholas F. Brady set out to raise funds and got them from legendary patron and collector Paul Mellon, the son of the NGA’s founder. The piece was dedicated in 1987.

The Shirleys stress that the reconstruction, too, has taken far more than money. The Calder Foundation, run by Calder’s grandson Alexander S.C. Rower, found evidence in its archives that the mobile had not been realized exactly as Calder envisioned. The newly conserved Mountains and Clouds takes advantage of new technologies to bring it in line with the artist’s intentions. Shirley added that a “determined team of solutions-oriented senators from both sides of the aisle” was crucial to realizing the work’s restoration, as well as “a devoted interagency group of government staff under the guidance of the Architect of the Capitol.”

Installation was began in late August. “Kim and I are looking forward to the moment when the motor is turned on, and the mobile’s components begin to move slowly in the way Calder imagined,” Shirley said.

If there is some inspiration for D.C. politicians in all of this, it is perhaps subtle. “Calder was not a political artist,” Shirley said. “But the work’s symbolic power—its incredible demonstration of equilibrium and the unlikely harmony that can be achieved across different planes—is symbolically potent.”

Correction: The print version of this article, appearing in the 2026 Top 200 Collectors issue, misstated whom the Hart Senate Office Building is named after. It is Philip Hart, not Gary Hart.