Who is John Henry, what is his story based upon, and is his story real, or a Tall Tale? (Tall Tale meaning fake)

John Henry is an African American folk hero. He is said to have worked as a "steel-driving man"—a man tasked with hammering a steel drill into rock to make holes for explosives to blast the rock in constructing a railroad tunnel.

map scale refers to the relationship (or ratio) between distance on a map and the corresponding distance on the ground. for example, on a 1: 100000 scale map, 1cm on the map equals 1km on the ground.