useless trivia: What Word Means: An Editing Mark Indicating An Insertion?

Questions

-----------, Illinois was originally named Fort Dearborn, Indian Territory.?

------------------ set sail for the New World on a Friday in 1492.?

Cologne water, a mildly perfumed toilet water also known as eau de Cologne, has been made in -----------, West Germany since 1709.?

Columbus had three ships on his first American exploration. On his second expedition, --------- ships were under his command.?

In ancient ------, people committed suicide by eating a pound of salt.?