Why St. Louis firefighters hosed down the Gateway Arch in 1965 with no fire in sight

In 1965, firefighters sprayed cold water 600 feet up the Gateway Arch, and there was no fire. The final eight-foot piece no longer fit, and the morning sun had wiped out five of six spare inches. Instead of pushing the legs harder, the crew shrank the hot south leg with cold water until the steel contracted, the gap reopened, and the ironworkers slid the last piece home in thirteen minutes. Sources: • NPS — Gateway Arch Fact Sheet — https://www.nps.gov/jeff/planyourvisit/gateway-arch-fact-sheet.htm • NPS — Materials and Techniques — https://www.nps.gov/jeff/planyourvisit/materials-and-techniques.htm • NPS — Stabilizing Truss — https://www.nps.gov/jeff/planyourvisit/stabilizing-truss.htm