100′ of kinetic sculpture: Sandy Calder’s White Cascade | Photo: Bradley Maule

It’s well documented that the Ben Franklin Parkway serves the Philadelphia art and art history community as a sort of Calder Way. While it never quite achieved its intended Champs-Élysées status, the Parkway is nevertheless Philadelphia’s axis of art, bookended by—and centered on—the larger-than-life sculptures from three generations of the same family. Alexander Milne Calder’s masterwork William Penn is only the largest of hundreds of his sculptures adorning City Hall; his son Alexander Stirling Calder’s Swann Fountain frames the view of City Hall from Logan Circle in shades of summer mist. At the opposite end of the Parkway hangs Ghost, the mobile in the Philadelphia Museum of Art’s Great Stair Hall produced by the grandson, Alexander “Sandy” Calder. It’s one of only two mobiles on permanent display in Philadelphia by a native son who transformed modern sculpture. The other, White Cascade, not only dwarfs Ghost—it dwarfs all other mobiles. But you’d never know the largest mobile sculpture in the world is in Philadelphia unless you had a reason to go through security and enter the Federal Reserve Bank of Philadelphia.

The Philly Fed opened in 1976 amidst the Bicentennial hoopla on Independence Mall with a design from a young EwingCole firm and consulting from Pietro Belluschi, an encore collaboration of the same team that produced the Rohm and Haas Building two blocks over a decade before. The Philadelphia Redevelopment Authority’s Percent for Art program blessed the Federal Reserve Bank with two epochal sculptures: Beverly Pepper’s Phaedrus, visible on the north side of the building’s exterior next to WHYY, and Sandy Calder’s White Cascade, hanging from the skylight of the Fed’s eight-story, 130′ Eastburn Court. The Calder was especially a victory for Belluschi, who’d wanted a Calder mobile for the lobby of his landmark circa-1948 Equitable Building in Portland, Oregon, but was shot down because the building’s developer disliked mobiles. Instead, Belluschi painted his own Calder-inspired mural.

Mini-mobile: the smaller version of White Cascade faces Independence Mall and the Ben Franklin Bridge | Photo: Bradley Maule

Composed of stainless steel rods and 14 white aluminum discs, White Cascade measures 100′ from top to bottom, and 60′ across at its widest. With an electric motor mounted to the atrium’s ceiling, it rotates on a radius of 32.5′ so slowly it’s imperceptible. Including the motor, the mobile weighs roughly 10 tons. (For comparison, Pepper’s stationary steel Phaedrus weighs 12 tons.) A smaller, working (and non-motorized) model of the mobile was also bought by the Fed, and hangs from the ceiling on the third floor.

Its sheer size made White Cascade double as a sort of capstone for Calder’s career. Installed over two days in May 1976, Calder lived to see the dedication of one of his last works of art before passing away on November 11, 1976. That same year, he designed his final work of art, the 76′ Untitled (his largest non-motorized mobile), installed in the National Gallery of Art in 1977.

While you can’t just walk into the Federal Reserve Bank off the street, you can visit Money in Motion, the Fed’s permanent exhibit on money, banking, and America’s financial history. Enter off of Sixth Street (across from the National Constitution Center) and be prepared to go through airport-style security. Once you’re on the inside, to view Calder’s White Cascade, just look up. You won’t miss it.

A career retrospective titled “Calder and Abstraction: From Avant-Garde to Iconic” is on view through July 27 at the Los Angeles County Museum of Art. The exhibition was curated by architect Frank Gehry, whose expansion of the Philadelphia Museum of Art officially goes on display there next Tuesday, July 1. Gehry’s expansion will renovate the Great Stair Hall, but it won’t touch Calder’s Ghost.

To launch a small gallery of White Cascade, click any of the images below.