Typically, a conscientious decorator hangs a wall with pictures, paintings and photographs. But connoisseur bike brand Aurumania proposes a new kind of frame for above the fireplace (or even a jaunt through town, if you're feeling brave): an eye-pleasingly simple bicycle, plated with 24-carat gold and embellished with 600 crystallized Swarovski Elements. Such unashamed idolatry is testimony to the fact that the world has gone increasingly bike mad over the past five years. Partly a result of ever-pressing ecological concerns, partly thanks to the trend among design fetishists for the minimal lines of fixed-gear bikes, the number of urbanites switching motors and seat belts for pedals and helmets has grown substantially––in Manhattan alone 236,000 people a day now jump on their saddles to get from A to B, while city officials are planning to build 50 miles of bike lanes a year to accommodate. On the homage front, this month New York's Museum of Arts and Design is mounting Bespoke: The Handbuilt Bicycle. The exhibition, organized by Michael Maharam (of Maharam textiles) and artisan bike builder Sacha White, collects the work of six international craftsmen—including White Himself and fellow US-based builders Mike Flanigan, Jeff Jones, Richard Sachs and J. Peter Weigle, as well as Italy's legendary Dario Pegoretti. Twenty-one hand-built steel bicycles, from road racers to tricycles, will be on display from May 11 through August 2010. To get you in the mood, we present a selection of images from Velo a new book from Gestalten that trawls the globe in search of the most unusual and extreme manifestations of pedal power worldwide, from small-scale prestige ateliers in Europe and the US to crackpot creations on the streets of Beijing.