It happens when nobody is watching." As the tagline on a poster raising awareness about domestic violence, that's not bad. But it was the poster itself that was truly attention-grabbing -- for it brought the issue of being watched (or not) to life.

The poster, placed in a bus shelter in Berlin, was a one-time installation sponsored by Amnesty International. When a person in the shelter was looking at the poster, he saw, along with the words, a photograph of an amiable couple: a stocky, professional-looking man in a blue oxford-cloth shirt, his arm around the shoulders of his girlfriend or wife.

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