Manhole covers uncovered

It's been widely observed that the Internet gives a platform to every interest group, not matter how obscure or bizarre: pick a subject, any subject, and there's probably a website about it, if not dozens. This truth was brought home to me today when, following a stray thought, I entered the search term 'Manhole covers' into Google. I was hoping to find a site celebrating this humble piece of street furniture and, sure enough, among the first 10 of the 64,700 entries (!) were such delights as Dan Heller's photos of manhole covers of the world (http://www.danheller.com/manholes.html); Drainspotting.com ("Drainspotting is all about paying attention to your surroundings. Manhole covers, drains, grates, trench covers--someone had to design all of these. Functional and ornamental, there's a lot of interesting stuff happening down by your feet."); and manhole covers of Tokyo (http://www.eps.vic.edu.au/japan/cover.htm). I also learnt about Art Underfoot, a competition to design new manhole covers held by the city of Vancouver earlier this year.
Most interesting of all was an article on 'Manhole covers of London' posted on online magazine, Ruavista. With a strapline of 'Signs of the City', Ruavista is a semiotician's dream. Founder Marc Voelgel outlines the magazine's philosophy thus: "Ruavista seeks to organize the streets [sic] wealth and to share it with the greatest number of people worldwide and strives to promote a new form of urban tourism based upon visiting ordinary streets and paying attention to details rather than famous spots and beautiful architecture."
In practice, this means such delights as articles on Brazilian motel signs and Parisian wall advertisements, real audio files recorded in streets around the world and a photo forum open to anyone submitting photos "provided they address the theme of the street." Read more at: http://www.ruavista.com.