The U.S. Air Force's Project Blue Book, which ran from 1952 to 1969, investigated reports of what?

Which group of nine Black teenagers was falsely accused of a crime in Alabama in 1931, leading to landmark Supreme Cour… By 1959, after just 11 years in business, which company was the world's leading motorcycle manufacturer? By 1962, which fluoride toothpaste had become the best-selling toothpaste in the U.S.? In 1965, which muscular Austrian teenager won the title of Junior Mr. Europe? By 1970, which former Harvard lecturer and 1960s psychedelic guru was on the run and living in Algeria? By the 1976 Olympics, which muscle-building drugs had been banned for Olympic competitors? By 1980, a global vaccination effort had eradicated which disease, the first human disease ever wiped out? In 2003, which energy source produced about 20 percent of U.S. electricity at plants like Palo Verde in Arizona?