Beaumaris Gaol was designed by Hansom and Welch, and was built in 1829. It was expanded in 1867 to accommodate approximately 30 inmates but was closed just 11 years later. The building then became a police station until the 1950s when it became a children's clinic and lastly a museum in 1974. During the Second World War the town's air raid siren was located in the gaol and was kept in operation during the Cold War in case of nuclear attacks. The gaol's chapel is not original to the building, and the pews and pulpit were sourced from a chapel being renovated elsewhere on the island. It is possible to tell that the pews are not the original ones as the numbering sequence is out of order and they are not fixed to the floor. The prison regime may appear brutal to a modern visitor, but in its day it was seen as humane improvement on earlier gaols. Even so, methods of keeping criminals in check included chains, whippings and isolation in a dark cell for up to three days. It has one of the last working treadmills in Britain. The treadmill at Beaumaris is unusual in that it pumped water to the top of the building for use in the cells, meaning that the prisoners were not forced to work for no reason. Two hangings took place at Beaumaris. The first was that of William Griffith, in 1830, for the attempted murder of his first wife. The second execution was that of Richard Rowlands in 1862, for murdering his father in law. He protested his innocence right up to the final moment and legend has it that he cursed the church clock from the gallows, saying that if he were innocent the four faces of the nearby church clock would never show the same time. Both men were buried in within the walls of the gaol in a lime pit, but the exact location of their burial is unknown. The metal rivets which held the gallows in place, along with the two doors which the condemned man passed through can still be seen from the street outside the gaol walls.The only prisoner to escape from the gaol was Owen Morris, who escaped on 7 January 1859, using rope he had stolen whilst working with it. He broke his leg whilst escaping, but made out of the town, before being recaptured.