A: London, England, United Kingdom
The workshop of inventor James Watt, containing all the furniture, the floorboards and door, window and skylight, and 8,4320 objects, essentially as they were left upon Watt's death in 1819, are preserved in the Science Museum, London.
"The workshop was in the attic of Watt's home, Heathfield, outside Birmingham. Watt spent a lot of time in the workshop after his retirement in 1800, partly to escape his second wife. His main project in the workshop was copying sculpture, for which he developed the two large copy-mills which dominate the workshop space. Upon Watt's death the room was sealed and, bar a few VIP visits by intrigued VIP visitors in the 1860s, left untouched until 1924. In that year, Heathfield faced demolition, and the room was dismantled and carefully shipped to the Science Museum" (Science Museum website, accessed 06-03-2011).
"It [Watt's workshop] remained on display for visitors for many years, but was walled-off when the gallery it was housed in closed. The workshop remained intact, and preserved, and in March 2011 was again put on public display as part of a new permanent Science Museum exhibition, 'James Watt and our world' "(Wikipedia article on James Watt, accessed 06-03-2011).