We often delight in the simple pleasure of running a stick along a set of railings, making a lovely "clack-clack-clack" sound. greyworld tuned these railings so that when you ran a stick along them they played "The Girl from Ipanema."
Created without permissions in cities around Europe, many versions have disappeared. But some still remain.
To find them, all you need is a stick.
Below are some shots from 1996, from an appearance on "The Big Breakfast Show," Channel 4 (UK)