Drilling for oil under the Upper Rhine plain in 1911 struck thermal water instead, and Krozingen turned into a spa town; the prefix Bad was granted in 1933. Its Kurhaus was finished in 1959 to plans by Horst Linde and enlarged in 1982, and it stands inside a Kurpark of forty hectares, the centre of gravity for everything the town puts on indoors. Its concerts run alongside the older Schlosskonzerte in the town's castle, where a collection of some fifty historical keyboard instruments is still played.