Sunday marks 10 years since the bombing of the Boston Marathon.

On April 15, 2013, two pressure-cooker bombs detonated 11 seconds apart near the finish line of the iconic 26-mile race.

Three people were killed and more than 500 others were hurt.

The bombing led to a large-scale manhunt for the suspects -- brothers Dzhokhar and Tamerlan Tsarnaev. Tamerlan was killed during the manhunt and Dzhokhar was arrested and eventually sentenced to death. He is currently being held at a supermax security prison in Colorado.

This year's race takes place Monday and preparations are currently underway. Crews laid down the iconic finish line across Boylston Street on Thursday. There's also a whole network of structures and technology needed to host the finish line for the marathon's 30,000 runners.

Thomas O'Grady, a native of the Capital Region, ran in the Boston Marathon in 2013.

O'Grady had crossed the finish line shortly before the first bomb went off and continues to look back at how close he and his family had been to the tragedy.”

"Our son was like four or five months old at the time, with some of our closest friends and they had been within like five feet of where that first bomb went off,” O'Grady said. “So, you know, just trying to process how lucky I was that I had finished and everybody that was there to cheer me on had gotten out safely."

O'Grady is set to run in this year's marathon.