Originally known as "Russian Mountains" -- literally, large ice slides devised to keep Russians happy under the Czar's monarchist rule. The constructions were refined in Paris, where they used a slide of metal rollers instead of ice, as well as Coney Island in New York. With the advent of tubular steel track, inversions such as loops and corkscrews were possible -- and perfected. So thank a Russian the next time yer hurtling down a 200-foot drop at speeds approaching 75 miles per hour.