An amazing interactive view of Yemen's capital, a city that has been continuously inhabited for more tha 2500 years. I love the infinite variablity of the vernacular style, the contrast of all those arches and windows and carved gypsum fanlights on facade after facade. Though they look quite contemporary, many of the flat-roofed multistory buildings in the old city are hundreds of years old. For much much more, see this lovely free-to-download book, The old walled city of San'a'.