Colmar is a slow-walking city. The medieval core is small enough to cross in fifteen minutes but you will want to spend two or three days here — wandering the Petite Venise canals, looping the old artisan quarters, and visiting the Unterlinden's Issenheim Altarpiece, which is reason enough on its own. From late November to late December the Christmas markets transform every square into a cluster of wooden chalets selling vin chaud and bredele biscuits.