February 17, 1883: A Mr. Ashwell, of Herne Hill, London, patented the Vacant/Engaged toilet door sign.

Not much to crow about, huh? Well, consider this:
Exactly 19 years and 10 months later, Orville and Wilbur Wright flew their Dayton, Ohio born device 120 feet in 12 seconds on a beach in Kitty Hawk, North Carolina.

in 1596, John Harrington invented the first indoor water-closet.

In 1913, a brilliant Russian combined all three, and invented the first airborne toilet...well, okay, so maybe it didn't have the illuminated "Occupied/Vacant" sign, but at least the users didn't have to worry about Tom Ridge.