The 45th annual Bank of America Shamrock Shuffle brought a sea of green to Grant Park on Sunday.

The event takes place a week after the Chicago River dyeing and continues with St. Patrick's Day celebrations.

"The race energy is so fun. It kicks off the running season. It's just a great way to see the city in a unique way, because all of the streets are closed," said runner Mallie Dowling.

The event attracts runners from all skill sets.

"Basically, the first medal I have won in racing and running. It felt great," said runner Christopher Diaz.

For others, this race has become a tradition.

"I had a blast last year and I got addicted to running, it's the start of the running season. So, I had to come back," said runner Filip Pancerz.

"Doing it for the vibes. You see me in a tank top, cold, windy. Everyone's coming to run," said runner Alex Vo.

The chilly temperatures did not stop thousands from taking part of the 2-mile walk along the lakefront or the 8K through downtown. Chicago Mayor Brandon Johnson welcomed the runners at the start of the race.

"This race brings energy to our parks, our streets, supports local businesses, and showcases the greatest freaking city in the world, the city of Chicago," Johnson said.

The event kicks off the start of the outdoor running season in the city, with many more events planned for runners to participate in.

"This is the beginning of our Bank of America Chicago distance series. It starts with the 8K, the Shamrock Shuffle. The beginning of the running season. Then, we move to the half marathon, the 13.1 on the West Side in June. And then, it all culminates right back here with the Bank of America Chicago Marathon," said Bank of America Chicago President Rita Cook.

"It's such a privilege to be healthy enough to run and being among other runners. It's awesome," said runner Mallie Dowling.