The New York City Marathon on Sunday broke the record for the world's largest marathon, with 55,646 runners crossing the finish line in Central Park, organisers said. That beat the record set by Berlin's Marathon in September,

As the race continues, the challenges increase with inclines on First Ave into The Bronx and the rolling hills of Central Park in the final miles, making New York a yo-yo of easy and hard miles. This relentless design isn’t all that slows runners down.