The Leibniz Institute for Astrophysics Potsdam (AIP) and the Centro Astronómico Hispano en Andalucía, Observatorio de Calar Alto (CAHA), jointly celebrate 25 years of operation of PMAS, the Potsdam Multi-Aperture Spectrophotometer: It was on May 29th, 2001, when the PMAS team, supported by CAHA staff, achieved First Light for the then new instrument at the 3.5m Telescope on Calar Alto.