The Ultra Trail du Mont Blanc (UTMB) starts today in Chamonix (CCC) and you can watch it live below.
The 171km event is one of the most hotly contested races in the world.
The winners are expected through around 20 hours. Yao Miao hopes to be come the first Chinese person to win the UTMB, matching her feat at the CCC last year.
The UTMB is a festival of running, with numerous races over the course of the week. Along with the TDS, the other major races are the OCC, CCC and the full 171km UTMB itself.