Animals on the Underground is an on-going project that casts the London Underground as a wild menagerie of elusive animals, who disappear in and out the thicket of abstract lines which comprise the map of the Tube. The project began in 1988, when the first animal, the elephant, was spotted. Since then a vast array of critters, both wild and domesticated, has been added to the roster of subterranean animals, from playful dogs and soaring pigeons to strutting baby rhinos and quiescent sperm whales. Their form and features are determined by the strokes and folds of the map's meandering beveled-edge lines, with the creatures sometimes fitting snugly within the Underground's negative spaces but more frequently extending across the city's skewed geography to encompass a whole series of train lines. New animals are constantly revealing themselves, so one must be always on the lookout.