The most extreme tornado in recorded history was the Tri-State Tornado, which spread through parts of Missouri, Illinois, and Indiana on March 18, 1925. It is considered an F5, though tornadoes were not ranked on any scale in that era. It holds records for longest path length at 219 miles (352 km), longest duration at about 3½ hours, and fastest forward speed for a significant tornado at 73 mph (117 km/h) anywhere on Earth.