On this day in 1873 came Der Krach, as the Vienna stock market augured in, sending ripples across Europe which would eventually spread to the U.S., triggering a six-year-plus economic slump that would be referred to as "The Great Depression" until a greater one came along and they had to rename this one.
Central Europe and the U.S. were both in the midst of postwar booms, as there was construction and business growth a-go-go in newly unified Germany and re-unified America. Railroads were the dot-coms of the day, drawing speculative investments from people who probably should have been investing in next week's grocery bill rather than The Next Big Thing.
Predictably as the sunrise, the music stopped and there weren't enough chairs to go around and businesses failed. In the U.S., more than a hundred railroads went toes up over a few years and railway construction fell to less than a quarter of its previous pace. As can be imagined, that led to a lot of unemployed people, and the remaining employed ones went on strike against the low wages paid by the profit-strapped surviving railroads.
Things were bad enough that the Democrats, regarded as being on the wrong side of public opinion in the recent Civil War, retook the House of Representatives for the first time since that war.