Drainspotting by Remo Camerota

The Japanese visual phenomenon does not stop with their bright billboards and interactive advertising. Now you can find these beautiful manhole artworks all over the city! Some of the finest manhole cover art has been collected by “Drainspotter” Remo Camerota.

He even created a iPad/iPhone app and published a book about it.

More info on Drainspottingbook & The Guardian