Misc: A "ivory" wedding anniversary is celebrated after how many years?

Questions

In which film did Marlene Dietrich sing "See What the Boys in the Backroom Will Have"?

Which Swedish naturalist developed the system of plant and animal classification which is still used today?

Which European capital city's name translates into English as "Merchants Haven"?

In Great Expectations, what was the occupation of Joe Gargery?

In a standard game of cricket, what is the maximum number of people that can be on the field of play at any one time during play?