1985: At long last, after 193 years, a sitting U.S. President visits the floor of the New York Stock Exchange, as Ronald Reagan comes to ring the bell that opens trading. It's official: The U.S. government finally thinks it's okay for investors to make money.

New York Stock Exchange flyer, "Key Dates in the History of the New York Stock Exchange," 1992.

1979: A minor malfunction occurs in a cooling mechanism at a power plant in Pennsylvania. One technical error follows another until the malfunction has escalated into a "meltdown." The name of the power plant is Three Mile Island, and it becomes the graveyard of the American nuclear power industry, which once held out the promise of cheap, safe, clean energy for all.