Apparently, this indoor swimming pool at 71 Sihlstrasse was built between 1939 and 1941 with construction delayed because of the difficulty of getting materials due to WWII.  Ironically, a recent refurbishment, costing 42 million Swiss francs, took much longer than expected as a result of delayed and wrongly delivered materials.  However, the pool did reopen in 2013.  It features a 50-metre pool with 6 swimming lanes, two 1m diving boards, a pool for non-swimmers and a sauna.