What with the Festival and all those students, the burghers of Edinburgh are probably used to strange nocturnal apparitions. But even they may blink when nearly 8,000 women (and a few men), wearing brightly-decorated bras, power-walk through their streets in the middle of the night on June 24.
Among those in the marathon-length charity Moonwalk will be 10 staff from Oakworth primary in Keighley, West Yorkshire. "We'll be going under the name of the Oakworth Sole Sisters," says Jeanette Osborne, a teaching assistant and a veteran of the Three Peaks Challenge. "We'll put pink footprints on our tracksuits and flashing lights on the bras."
Each Sole Sister has paid pound;40 to enter the event, sponsored by Playtex to fund breast cancer research. Each must raise at least pound;100 more. Will they stay on to carouse after they stagger across the finish line? "If we're still awake," says Ms Osborne.