“We heard that first boom, and then just fire and smoke coming up,” one onlooker told ABC News afterward. The large span fell into the river below. The structure in the background of the photographs is the $3.9-billion, 3.1-mile Governor Mario M. Cuomo Bridge, which opened in 2017 and 2018 and connects Tarrytown and South Nyack, New York, over the Hudson River. The old bridge, the Tappan Zee, dates back to 1955, and while the original plan had been to take it apart without explosives, concerns over the safety of the old structure shifted the plan to the more dramatic option. According to the Rockland/Westchester Journal News, chains positioned in the river will help salvage crews recover the remnants of the structure. And while the destruction of the old bridge is pretty awesome-looking, the moment is a crucial reminder that much of the infrastructure in the U.S. and abroad is aging, and likely deserves a similar end in the next few years. In fact, the United States is home to more than half a million bridges, 39 percent of which are at least five decades old, according to a 2017 Infrastructure Report Card. As of 2016, more than 50,000 bridges in the country were “structurally deficient.” Millions of trips are made across “deficient” bridges each day. There’s reason for both pessimism and optimism on the topic. The bad news? According to the same Infrastructure Report Card from the American Society of Civil Engineers, America’s bridges need some $123 billion worth of rehab work. The good? The number of deficient bridges is actually falling: in 2007, more than 12 percent of U.S. bridges were structurally deficient. As of 2016, that number had fallen to 9.1 percent. Now, at least, there’s one less old bridge to worry about.