When it comes to wonderful, inexplicable old mechanical door locks, Sweden has all the luck! The rust on this Swedish door lock has not only become an artistic part of it, from the photographer’s point of view, but seems to have become part of the actual structure! If it were ever cleaned, scrubbed and de-rusted, I think it might fall apart.
You can tell how stiff it would be, and how many times you would have to curse at the lock to make it open, by looking at the metal spiral in the bottom left corner. This is what the key would turn … but only with much stronger fingers than mine!