Two robotic legged squad support system (LS3) machines by the Defense Advanced Research Project Agency follow a technician during a demonstration at Joint Base Myer-Henderson Hall, Virginia, on September 10, 2012. (U.S. Marine Corps photo by Sgt. Mallory S. VanderSchans via The Atlantic)

On Guard, Indonesia, by Riksa Dewantara. The explosive eruption and loud rumbling of the Mount Bromo volcano in Bromo Semeru Tengger national park scared the horse causing it to rear up onto its hind legs. Second place, Journeys and Adventures category. (Photo by Riksa Dewantara/SIPA Contest)

Arachnids category 3rd place: dancing spider by Raed Ammari. Male jumping spiders (in this case a Phidippus insignarius) perform a courtship dance in which they almost form a heart shape with their legs. This one was shot in Colorado. (Photo by Raed Ammari/Luminar Bug Photographer of the Year 2020)

Manchester City's Phil Foden celebrates after scoring his side's sixth goal during the Champions League round of 16 second leg, soccer match between Manchester City and Schalke 04 at Etihad stadium in Manchester, England, Tuesday, March 12, 2019. (Photo by Dave Thompson/AP Photo)

Alexia Putellas of FC Barcelona celebrates victory with fans following the UEFA Women's Champions League Quarter Final Second Leg match between FC Barcelona and Real Madrid at Camp Nou on March 30, 2022 in Barcelona, Spain. (Photo by Alex Caparros – UEFA/UEFA via Getty Images)

A close up shows Ukraine's Hanna Ryzhykova leg breaking a hurdle before crashing out as she competes in the women's 400m hurdles heats during the European Athletics Championships at the Letzigrund stadium in Zurich on August 13, 2014. (Photo by Olivier Morin/AFP Photo)

A tattoo of Captain America drawn by artist Sean Karon on the leg of client Ron Raucci at the Hampton Roads Tattoo Festival in Virginia, on March 2, 2012. The tattoo was completed from start to finish in one five-and-a-half hour session and won the prestigious “tattoo of the day” contest. (Photo by Jason Reed/Reuters)

Street photographer Yassine Alaoui Ismaili follows 16-year-old Emeer Guesmi, aka B-boy Zulu Rema, as he trains and performs breakdance moves – all without the use of his legs. At a breakdance championship in Tunisia, Casablanca-based street photographer Yassine Alaoui Ismaili noticed an unusual competitor: Emeer Guesmi, dancing without the aid of his lower legs. He started following him as he trained and performed. (Photo by Yassine Alaoui Ismaili/The Guardian)