It was a sight not likely to be seen again in the skies over Greenwich, Conn.—or anywhere else. A helicopter whirled over the 24-acre estate of Joseph Hirshhorn, 75, a multimillionaire from investments and mining (he is known as "the uranium king") and owner of the largest private sculpture collection in the world. Down through the branches crashed the whirlybird's hook and cable. Then with a roar that tore the acorns off the trees and sent them bouncing like hailstones, the chopper slowly lifted one mighty masterpiece of 19th and 20th century sculpture after another up into the sky.

Their eventual destination is the new Hirshhorn Museum and Sculpture Garden at the Smithsonian Institution on the Mall in Washington. When it opens in October, it will show the pick of Hirshhorn's 2,000 sculptures and 4,000 paintings, all valued at $125 million.

The airlift was both a spectacular send-off and a practical solution to a unique moving problem. "With cranes, it would have been a long song and dance," explains Hirshhorn's personal art curator, Jay Rogers. "With the helicopter, we moved 12 pieces in two hours." They were carefully set onto flatbed trucks which took them to the capital. What about the expense? "What's the difference," shrugged Joe Hirshhorn. "I'm paying for it."

The afternoon was not without its scary moments. Manzú's 280-pound Monumental Standing Cardinal began spinning wildly at the end of the helicopter's 75-foot cable, sending the 100-odd spectators scurrying for shelter.

With the works removed, Hirshhorn's carefully landscaped gardens had a barren look. But he was reconciled. "Twenty-one million people a year visit Washington," he said, "and these things will get much more exposure there than here." Curator Rogers added, "The place won't look so empty after a while. He'll keep buying more."