Atlas was built by Boston Dynamics for the DARPA Robotics Challenge and shown publicly on 11 July 2013 as a disaster-response research platform: a 188 cm, 150 kg biped with 28 hydraulically actuated joints, a LIDAR-and-stereo sensor head and, at first, a power tether. Competing teams wrote their own control software and drove it through valve turning, debris clearing and door opening under deliberately degraded communications. A 2015 revision cut the tether with an on-board battery, and a 2016 redesign made the robot markedly smaller and lighter. What outlived the challenge was the video record: backflips, parkour and box handling that defined the public image of a walking robot for a decade. Boston Dynamics retired the hydraulic line on 16 April 2024 with a farewell film, and unveiled the fully electric Atlas the next day.