Got to love the creativity that has gone into the Animals on the Underground site. I've often stared at those maps myself (wondering how to get from Southgate to Baker Street in less than an hour) but it took Paul Middlewick to see the pattern and spot the first album, an elephant, in 1988.
Now there's t-shirts you can buy, ecards you can send and it's all for the benefit of the International Fund for Animal Welfare.
Other than the dove, I think this tortoise is my favourite
Check out the great site on http://www.animalsontheunderground.com
EDIT: I see 73man has elevated this site to the status of truth before me.
The Animals on the Underground concept and images are the property of Grid24 Ltd. The London Underground logo and map © TfL Reg'd User No 05/4294.