The Man who Knew too much (1934)

The plot concerns a British couple on vacation in Switzerland, who witness the assassination of a spy. Before dying, the spy passes on to them some vital information. In order to maintain their silence, a group kidnaps their daughter. After following a series of leads, the couple discovers that the group intends to assassinate a European ambassador during a concert at the Royal Albert Hall.
The Man Who Knew Too Much is the only one of Hitchcock's films that he remade. The remake is in color and stars Jimmy Stewart and Doris Day. In his book-length interview with François Truffaut, Hitchcock/Truffaut (1967) Hitchcock said he considered his remake to be superior, saying that the 1934 version was the work of a talented amateur, while the 1956 version was the work of a professional.