A wooden Panopticon factory, capable of holding 5000 workers, was constructed by Samuel Bentham in Saint Petersburg , on the banks of the Neva River , between 1805 and 1808: its purpose was to educate and employ young men in trades connected with the navy. It burned down in 1818.  The Round Mill in Belper , Derbyshire, England, is supposed to have been built on the Panopticon principle with a central overseer. Designed by William Strutt , and constructed in 1811, it had fallen into disuse by the beginning of the 20th century and was demolished in 1959.  The Worcester State Hospital , Massachusetts, USA, constructed in the late 19th century, extensively employed panoptic structures to allow more efficient observation of the wards. It was considered a model facility at the time.