The Boston Marathon is supposed to be a day of celebration.
Boston nearly shuts down to honor the 30,000 runners who qualify to run in the annual elite race.
This year, more than 200 Tennesseans participated, including 53 runners from the Nashville area.
On Monday, four hours after the marathon began, celebration turned to devastation for all those in attendance when two bombs exploded near the finish line.
"I've never experienced anything like it. The ground shook," said Scott Alexander.
Alexander went to Boston with seven other runners and eight spectators from the Nolensville Running Club. He crossed the finish line 20 minutes before the first bomb exploded.
"You could see others, I guess friends and family of runners, who were still out there on the course, just in tears and shaking," he said.
"My heart dropped," said Ashlee Tidwell, who followed the aftermath on television and social media.
"I was just hoping no one I knew was hurt," she said.
Tidwell works at Fleet Feet Sports in Brentwood and knows several runners who competed, including her boss, store owner Christi Beth Adams.
"I know Christi Beth had just finished, and said that she had heard two booms, and thought that they were celebratory cannons," she said. "And then people were running towards her and [she] realized something was wrong."
Alexander, his teammates, and Adams crossed the finish line safely with family and friends there to greet them before the blasts.
Elizabeth Scoville went to Boston to watch her brother race Monday.
Scoville said her brother finished the race before the four-hour mark. She told Nashville's News 2 her family is lucky her brother is a fast runner.
"Right where we were watching the marathon was just outside the Lenox Hotel, really close to the finish line," said Scoville. "And we are so lucky that Morgan is a really fast runner because if he wasn't we definitely could have been there during the explosions, which is just horrible."
Scoville said she left for the airport as soon as her brother finished the race, but eventually she was able to contact her family to make sure they were okay.
An estimated 4,000 runners were still on the course when the bombs exploded, including Middle Tennessee State University Professor Paula Thomas.
"To think that all that joy, and all of that celebration, and all those people waiting on the finish line, [and] this to happen, it's just not comprehensible," she said.
At mile 24, she was told the race was over, but she didn't stop.
"I'm angry that anybody would do this today, and I'm going to run my marathon," she said.
With her daughter and another runner by her side, Thomas finished the 26.2 mile marathon off-course, for herself, her charity (American Medical Athletic Association), and her fellow runners who could not finish.