20,000 people are taking to the streets for the Dublin Marathon this morning.
The event is the fifth largest marathon in Europe and is being live streamed until 5pm.
The first wave of runners set off at 9am.
Anyone coming in to watch the event is being warned of heavy traffic restrictions around the city.
Jim Aughney, Race Director says the conditions are perfect.
He said: "It looks like about 12 degrees with a slight breeze making it a real feel of about 10 degrees which is absolutely perfect for the runners.
"It is ideal for the runner and spectators alike because they will be able to stay out, they will be dry and able to cheer everybody around the route ."