Animals on the Underground, a collection of line-art animals discovered within the London tube map.
The animals, created using the tube lines, stations and junctions of the London Underground map were first spotted by Paul Middlewick in 1988. The original animal, the elephant was discovered while Paul was staring at the tube map during his daily journey home from work. Since then, the elephant has been joined by many others from bats to bottlenose whales.
There are more than thirty animals so far, maybe you can find another one?