What is "alster-schwimmhalle"

The Alster-Schwimmhalle is one of Germany's larger aquatics centers, located in the Hamburg district of Hohenfelde. Originally opened in 1973, it was substantially renovated in 2007. Over the years, it has regularly hosted various national and international swimming competitions.

The Alster-Schwimmhalle is notable for its by double hyperbolic-paraboloid concrete-shell roof structure, designed by Jörg Schlaich, then partner at Stuttgart-based engineering firm Leonhardt & Andrä. Resting on three bearings and only thin, the concrete roof remains one the world's largest of its kind. Reminiscent of a butterfly –an allegory to its function as a swimming venue– the airy roof structure earned the Alsterschwimmhalle its nickname as "Schwimmoper" (Aquatic Opera).