16th IAAF World Athletics Championships London 2017 - Day One

LONDON, ENGLAND - AUGUST 04: Gabriela Stafford of Canada leads the pack during the Womens 1500m heats during day one of the 16th IAAF World Athletics Championships London 2017 at The London Stadium on August 4, 2017 in London, United Kingdom. (Photo by Shaun Botterill/Getty Images)