Järvafältet, where Kista, Husby and other suburbs of the north-west of Stockholm are located, was once a military area. There are still some remnants from that era - foxholes, concrete pillboxes, and a secret railway called "Krutbanan" ("Gunpowder Railway").
I had intended to cover (almost) the whole of Järvafältet, from Ursvik and up to Rotebroleden, but like many ambitious intents, this one ended up in the pile marked "some other day". A column in Dagens Nyheter[a] changed that. Apparently, Krutbanan is Sweden's most secret railway. Or was, at any rate - there isn't any actual rail worth mentioning left[b].