I agree with Darktan - leash training a cat is totally doable if you start when it's a kitten. My cat is about a year old and I started taking him out on a harness/leash when he as just a couple months old. Once he realized that the harness does not, in fact, paralyze him, and that I wouldn't let him outside without that gear, he accepted his fate and now actually likes going out on walks. Admittedly the exercise isn't as good as walking a dog, seeing as he meanders around at his lazy cat-pace, but a good time is had by all involved. :)
I think I recall a similar tradition at the Great Wall of China - the thought process behind that padlock collection is that if one leaves something behind there, then that person is bound to return to that site again during his or her lifetime.