By the turn of the century it had become obvious that wrought iron lacked the strength to support the increasing weight of rail traffic, and engineers brought about an era of superlative steel bridges. Regarded as ugly and ponderous by the architectural critics of the time, the bridges have survived their detractors and are today justly seen as works of utilitarian grandeur. The two shown here were designed by the greatest engineers of the era, Gustav Lindenthal and Ralph Modjeski. Linden that’s massive Sciotoville Bridge over the Ohio River, below, was completed in 1917. Modjeski’s 1930 Mid-Hudson Bridge at Poughkeepsie, New York, at right, is considered to be one of the most beautiful suspension bridges in the world.