Competing for Switzerland, Céline Dion won which song contest in 1988?

Which company introduced the first Magnum revolver, the .357, in 1935? For much of the 20th century, which company was Delaware's largest private employer? Which company makes Ho Hos snack cakes? Which Handel oratorio, his most famous, first performed in 1742, has very little plot compared to his others? Competition from Chevrolet spurred Henry Ford to introduce which new model in 1927? Hurst Castle, completed around 1544 to protect the Hampshire coast, was built by which English king? The Ponte Vecchio, completed in 1345, crosses the Arno River in which city? Which Berlin landmark, completed in 1791, reopened in 1989 after being closed for 28 years?