The men's marathon is traditionally raced on the last day of the Olympics.
Often, the marathon is raced in the late afternoon so that the finishers can hit a finish line in the Olympic Stadium.
London deviated from that however and raced the 26.1 miles in the streets of London starting at 11 a.m.
This allowed thousands of people to line the course as spectators and enjoy a free marathon experience.
It also allowed runners to go past London's most iconic landmarks.
Deirdre shot these photos near the Tower of London.
Many fans were on the course several hours before the race to get the perfect spot to see the race. (
Today's race high was 77 degrees.
Marathon rule of thumb is add 20 degrees to the actual temperature, and you know what it feels like to be running the race.
The sun was blazing at times, and you could see athletes struggling in the heat.
Deirdre Fitzpatrick and Erin McManamon watch the men's marathon.
Spectators liked this stretch of the course because this is where the runners did their turnaround.
That allowed fans to see the athletes go by on three occasions.
This photo shows the giant camera on the boom in the air swooping in to get runners as they turned and fans as they cheered them on.
Des Moines, IA