The insanely difficult feat of the triple axel, broken down

    Mirai Nagasu

    (CNN)She's been training this dangerous jump for years. And finally, under the bask of Olympic lights, Mirai Nagasu did something no other American woman has ever done at the Olympics:

    She landed a triple axel.
    Why this is so massively impressive:
      The axel jump was first invented in 1882 — by a guy named Axel Paulsen. But he only did a single axel. It took more than 90 years for the first man to land a triple axel.
      And it wasn't until 1991 that the first American woman landed a triple axel. That was Tonya Harding at the 1991 US championships.
      At the Olympic level, Nagasu is only the third woman -- and the first American woman -- to successfully complete the triple axel; the other two are Japanese skaters Midori Ito and Mao Asada.
      Why the triple axel is so rare to pull off: