It's the seconds biggest running race in America, and it is held every year on Memorial Day in Boulder Colorado.
This year over 50,000 runners celebrated the Memorial Day holiday with a 10-Kilometer run at the 2010 Bolder Boulder.
After the race many runners and their families stayed for one of the largest Memorial Day remembrances in the country.
Click HERE to check out last year's race.
So what's it like to spend Memorial Day running?
Roman Mica caught up with runners from all over the country as they tested themselves against the clock.
These are their stories.
Follow on twitter @ everymantri or view latest
videos on YouTube .