Which U.S. coin, made of a copper-nickel alloy starting in 1866, took over the role of the silver half dime?

After being crowned emperor of Ethiopia in 1930, who introduced a written constitution and moved to abolish slavery? After being elected mayor of Atlanta in 1916, Asa Candler gave control of which company to his children? After being expelled as editor of the socialist paper Avanti! in 1914, who founded his own paper and later the Fascist… After 27 years in prison, who was elected president of South Africa in 1994? After losing World Series after World Series, which team, nicknamed "Dem Bums", finally won in 1955? After being named host of the 2001 Oscar broadcast, which "Roxanne" star cracked, "If you can't win 'em, join 'em"? After being overthrown by Fidel Castro in 1959, which Cuban dictator spent his last 14 years in exile? After being rebuilt in 1855, the Imperial Palace in which former Japanese capital was home to just two emperors?