USTA tennis center’s retractable roof

The U.S. Tennis Association unveiled its retractable roof over the main court at the USTA Billie Jean King National Tennis Center in Queens on Aug. 2. It cost $150 million and took more than two years to install. Moving at a speed up to 25 feet per minute, the roof over the 23,771-capacity stadium is built to close or open in under seven minutes. The 62,500 square-foot opening in the roof could fit 22 tennis courts.