Meet Cooper Lutkenhaus, 17, the phenom who became 800m world champion while at school

Cooper Lutkenhaus, a 17-year-old American, became track and field's youngest world champion after winning the 800m indoor gold in March. He followed that achievement by winning his first Diamond League race in Stockholm against a top-class field on Sunday. His performances have drawn widespread praise from rivals and comparisons to other teenage sporting phenoms such as Mirra Andreeva and Lamine Yamal.