![Missouri Once Had the World’s Largest Man-Made Tunnels Until Now](http://townsquare.media/site/462/files/2023/07/attachment-cave-diving.jpg?w=980&q=75)
Missouri Once Had the World’s Largest Man-Made Tunnels Until Now
Lead was king back in the late 1800s and when it was discovered in a cave in Missouri large tunnels were dug to collect the lead, However, after the tunnels flooded the cave become used for something else.