Lian Yunzhi has broken the women's world record for the 3x3x3 Rubik's Cube twice in three days. She first broke it with an average of 4.52 seconds and then 4.27 seconds, and became the only female cuber in the world to have an average time under 4.5 seconds. Over the past year, the six-year-old has spent about two to three hours a day on algorithm training. #RubiksCube #BBCNews