A robot dog in South Korea has made history by becoming the first four-legged robot to complete a full-length marathon without needing to recharge its batteries. Named RAIBO2, the advanced quadrupedal robot, developed by researchers at the Korea Advanced Institute of Science and Technology (KAIST), covered the 42-kilometer distance of the Sangju Dried Persimmon Marathon in a time of 4 hours, 19 minutes, and 52 seconds.