4. Lindenthal’s Hudson River Bridge

Rendering from Scientific American May 23, 1891

Beneath a tree on a (landlocked) college campus in New Jersey, there’s a cornerstone of a bridge that leads to nowhere. The stone is the only trace of a planned 6,000-foot-bridge that would have spanned the Hudson River from Manhattan’s 23rd Street at 10th Avenue to New Jersey. Originally laid in June 1895 at the corner of Garden and 12th Streets in Hoboken, the stone was only later moved to its current location at the Stevens Institute of Technology.
Had plans come to fruition, the massive structure would have been an iconic element of New York’s skyline. Even by modern-day standards, the size of the bridge is impressive: 200 feet wide and 200 feet high to accommodate 12 railroads, 24 traffic lanes and 2 pedestrian walks. The massive structure would have been double the length of the George Washington Bridge, and two supporting 825-foot-high towers would have been taller than the 792-foot Woolworth Building (the world’s tallest skyscraper at the time).