 Complete the following phrase:  Dibiasi won a silver medal in platform diving at the 1964 Summer Olympics, and went on to win gold in the same event at the next three Games 1968, 1972, and 1976. Dibiasi is the only Olympic diver to have won three successive gold medals, and he is the only diver to have won medals at four Summer Olympics. Greg Louganis, who won silver at his first Olympics in 1976, was prevented from attempting to replicate either feat by the 1980 Summer Olympics boycott. A silver in the springboard in 1968 gave him a record total of five Olympic medals. He also excelled at the first two FINA World Aquatic Championships 