The degraded oceanic climate which reigns in the plain of Alsace is favorable to the vines. It often generates haze that covers the vineyards and valleys in spring and winter. Wedged between the Vosges and the Black Forest, the Alsace plain is around 18 miles wide (30 km) and 105 miles long (170 km). Its Wine Route already existed in Celtic and Roman times, as attested by a milestone located downhill from the Haut-Koenigsbourg castle, at the exit of the village of Orschwiller.