Focke's wind tunnel

Focke's wind tunnel is a fully operational wind tunnel in the former private laboratory of the aviation pioneer Henrich Focke, co-founder of Focke-Wulf and designer of the first fully controllable helicopter, the Focke-Wulf Fw 61. Henrich Focke built the laboratory in 1960 at the age of 70 in the city of Bremen.

Until shortly before his death, in 1979, Focke continued aerodynamic studies in slow flight characteristics and the stability problem of helicopters. The rediscovery of his aerodynamic laboratory, together with its wind tunnel was regarded as a sensation for science and technology. Since 2004, the technical monument Focke Flight Laboratory is protected by law.

Source: Wikipedia