At the height of its activities, the Rad Lab employed nearly 4,000 people working on several continents. What began as a British-American effort to make microwave radar work, evolved into a centralized laboratory committed to understanding the theories behind experimental radar while solving its engineering problems. The Rad Lab formally closed on December 31, 1945, and its staff members resumed their peacetime activities. In its wake remained tons of surplus equipment and the concept for a basic research center that was to continue in RLE.