span at 1,750 feet between the towers. Includes an active subway line and never-used trolley stations on the span. San Francisco–Oakland Bay Bridge (USA, 1936). This was once the longest steel high-level bridge in the world (704 m). The eastern portion (a cantilever bridge) has been replaced with a self-anchored suspension bridge which is the longest of its type in the world. It is also the world's widest bridge. Golden Gate Bridge (USA, 1937), the longest suspension bridge from 1937 to 1964. It was also the world's tallest bridge from 1937 to 1993, and remains the tallest bridge in the United States. Mackinac Bridge (USA, 1957), the longest suspension bridge between anchorages in the Western hemisphere. Si Du River Bridge (China, 2009), the highest bridge in the world, with its deck around 500 meters above the surface of the river. Rod El Farag Bridge (Egypt, 2019), a modern Egyptian steel wire-cables based suspension bridge crossing the river Nile, which was completed in 2019 and holds the Guinness World Record for the widest suspension bridge in the world with a width of 67.3 meters, and with a span of 540 meters. Notable collapses Broughton Suspension Bridge (England) – Iron chain bridge built in 1826. One of Europe's first suspension bridges, it collapsed in 1831 due to mechanical resonance induced by troops marching in step. As a result of the incident, the British Army issued an order that troops should "break step" when crossing a bridge. Silver Bridge (USA) – Eyebar chain highway bridge, built in 1928, that collapsed in late 1967, killing forty-six people. The bridge had a low-redundancy design that was difficult to inspect. The collapse inspired legislation to ensure that older bridges were regularly inspected and maintained. Following the collapse a bridge of similar design was immediately closed and eventually demolished. A second similarly-designed bridge had been built with a higher margin of safety and remained in service until 1991. Tacoma Narrows Bridge, (USA), 853 m – 1940. The Tacoma Narrows bridge was vulnerable to structural vibration in sustained and moderately strong winds due to its plate-girder deck structure. Wind caused a phenomenon called aeroelastic fluttering that led to its collapse only months after completion. The collapse was captured on film. There were no human deaths in the collapse; several drivers escaped their cars on foot and reached the anchorages before the span dropped. Yarmouth suspension bridge (England) –