23. Quebec Bridge

Location: Quebec City, Canada

Year of Fail: 1907

Able to span long distances and easy to construct, the steel truss cantilever bridge was a major engineering breakthrough when invented in the mid 1800’s. At 1,800 feet, the Quebec Bridge over the St. Lawrence River is the longest bridge of this type in the world. Two collapses also make this one of the most catastrophic bridges in the world. While being constructed in 1907, a mistake in load capacity calculations caused a large chunk of the bridge to come crashing down on workers, killing 75 of the 86 present. While rebuilding the bridge in 1916, the central span slipped while being hoisted into place, killing another 13 workers.