High Quality Content by WIKIPEDIA articles! Building 20 (18 Vassar Street) was a temporary wooden structure hastily erected during World War II on the central campus of the Massachusetts Institute of Technology. Since it was always regarded as "temporary", it never received a formal name throughout its 55-year existence. The three-floor structure housed the Radiation Laboratory (or "Rad Lab"), where fundamental advances in physical electronics, electromagnetic properties of matter, microwave physics, and microwave communication principles were made, and which has been called one of "two prominent shrines of the triumph of science during the war". A former Rad Lab member said, "At one time, more than 20 percent of the physicists in the United States (including nine Nobel Prize winners) had worked in that building".