Valencia, Spain: A bit o'Calatrava

The City of Arts and Sciences played a big role in the financial crisis facing Valencia, Spain (along with the money spent to accommodate Formula One and the America's Cup), but the buildings themselves are quite nice. Santiago Calatrava is clearly paying homage to Antonio Gaudi, echoing his predecessor's way of using forms from the natural world to create fascinating buildings. He's even got a stylized conical chimney…

Paris: Start here

Any visit to Paris has to start with Notre Dame, one of the most beautiful things mankind has ever created, as well as perhaps the most impressive, from a technical standpoint. Begun in 1163, the building's scale is almost unimaginable until you're standing next to it, and it was in fact inconceivable (and unbuildable) prior to the advent of the flying buttresses that support the sides of the building. Beyond mere achievement, however, Notre Dame will always startle with its beauty, and with the wealth of details that delight (and sometimes frighten) the viewer at every turn.