March 28 (UPI) -- On this date in history: In 1881, P.T. Barnum and James A. Bailey merged their circuses to form The Greatest Show on Earth . The circus later merged with the Ringling Bros. to form Ringling Bros. and Barnum & Bailey Circus, which closed for five years beginning in 2017. Advertisement In 1939, Madrid surrendered to the nationalist forces of Generalissimo Francisco Franco in the Spanish Civil War. In 1968, the counterculture musical Hair opened on Broadway. In 1969, Dwight D.