And they're off! Runners decked out in layers - including trash bags - started under a trail of confetti as the Route 66 marathon got underway Sunday.
The annual event attracts thousands of runners who will go the distance of up to 26.2 miles in the marathon.
Half marathon and marathon relayers are also braving the frosty temperatures after an Arctic front left Green Country 20 degrees below normal.
Sunday's events started at 7th and Main and will finish up at Guthrie Green in the Brady Arts District.
There are many street closings as the course map goes through downtown to Riverside Drive, past Woodward Park, the University of Tulsa and back down 15th to the Brady Arts District.