What digit does not exist in Roman Numerals?

More Questions:

First minted in 2000, whose likeness was on the face-side of the US dollar coin?

What 1964 Broadway hit centered on a milkman and his five daughters?

Which character killed Aslan?

What Broadway team collaborated on "Flora the Red Menace" before writing "Cabaret" and "Chicago"?

The city of Santa Cruz is located on the shores of what bay?

What city dug the first subway?

What California peak, which erupted in 1915, is the world's largest lava dome?

What city is the capital of Turkey?

Actress Carrie Fisher and singer Edie Brickell have both been married to what musician?

What stadium hit do we owe to a pre-Civil War folk song and the Swedish dance band Rednex?

What album track was the first song the Beatles ever performed on their Ed Sullivan Show debut?

Which cowboy musical artist first recorded the song, Here Comes Santa Claus?

What country's space travellers have been called "taikonauts" since 1998?

When was Crazy Horse born?

Whose concert was the target of a terrorist attack in May, 2017, in Manchester, UK?