Leonardo da Vinci designed a 240 meters bridge it would have been the longest bridge in the world. His plan was ambitious. In 1502, a skeptical sultan rejected Leonardo's design as impossible, but 300 years civilization finally embraced the engineering principle - arches as supports - underlying the construction. The bridge has been constructed, in Norway. Now instead of spanning the Bosporus , his visionary creation was destined to span 500 years as a bridge to another millennium. Vebjorn Sand