In July 1874, the world’s first steel arch bridge to cross the Mississippi River was finished at St Louis. What general was given the honor of driving the ‘gold’ spike during the dedication ceremony?
Interestingly, about a month before the dedication, an elephant was led across the bridge to test its safety because people believed that elephants instinctively avoided unsafe structures. Now I'll have to check whether there's any truth to that belief.
President Ulysses S. Grant dedicated Eads Bridge in St. Louis on July 4, 1874, and General William T. Sherman drove the gold spike completing construction.
William T Sherman (8 February 1820 – 14 February 1891)
President Ulysses S. Grant dedicated the bridge on July 4, 1874, and General William T. Sherman drove the gold spike completing construction. wiki/Eads_Bridge
After testing the Eads Bridge with an elephant, President Ulysses Grant dedicated the bridge on 4th of July, 1874 with General William T. Sherman driving in the “gold” spike, and then 14 locomotives crossed the bridge to prove it was safe.
Wikipedia and https://www.nps.gov/jeff/learn/historyculture/upload/eads.pdf