This is industrial tourism at its best, allowing visitors to Łódź to penetrate the earth's core and visit the sewers that lie below. Designed by William Heerlein Lindley and put into action by Stefan Skrzywin, this red brick subterranean reservoir was originally opened in 1926, serving the original purpose to clean and purify the sewage produced by the natives. Running a length of 142 metres, and holding a capacity of 300,000 litres of water, it was finally shut down in the 1970s and allowed to gather rats and damp in equal measure. Reopened on May 28, 2008 the Dętka has now been fully restored, with your guided tour taking you past a catalogue of photographs and documents put together by Robert Kuśmirowski. Claustrophobics and other assorted weaklings should note the tunnel is 1.5 metres wide and 1.87 metres in height. Open May-Oct, Eng speaking guides available upon prior arrangement.