Belgian artist Francis Alys has a short "film" demonstrating the omnipresence of surveillance cameras. His demonstration? He brought a wild fox into Britain's National Portrait Gallery and used the security cameras to film it wandering through the empty galleries. "It spent more time in the Tudor room for some reason, possibly because it's darker, but I'm not sure I could confirm if there is a specific taste for one period or another."
The fox, named Bandit, is actually quite cute and it's amusing to watch him wander around. You can view the whole film here.