On Retronaut, Viktor Bulla's "Pioneers defense drill, Leningrad." It dates from 1937, four years before the Siege of Leningrad, and that makes the weirdness vivid and poignant. So many of the children here would have died in the Siege, or lived through it in the civil defense force, eating wallpaper paste and digging trenches. How brave and ready they must have felt in 1937, though.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.