Tourists chatted and walked around the memorial as Swain started to sing.
But midway through her rendition, the crowd fell silent.
Spectators started to gather around Swain and listen.
Then, at her high note, they started to cheer and applaud.
“People just started saying: ‘That was awesome. Thank you,’ ” Swain told the Tallahassee Democrat. “One lady had tears in her eyes.
“I was kind of glad it was over. It was like a sigh of relief.”
Bolden, an elder at Family Worship and Praise Center in Tallahassee, said Marcus Henderson, the music minister, shot the video.
Swain told the Democrat that the video was posted on YouTube later that day but it wasn’t until the next week that it caught fire, explaining: “Someone put it up on their Facebook page and the rest is history.”
Swain, who said she is assistant principal at Jefferson County Middle-High School in Monticello, Fla., is listed as Genleah Swain on the school district’s website.
Pastor Quincy Griffin Sr., from Family Worship and Praise Center, said he has known Swain for years — back when she was a trombonist and vocalist in the marching band at Florida A&M University.
Now, he said, she leads the worship and arts department at his church.
“It’s awesome now to let the world experience her voice beyond the four walls of the church,” Griffin told The Washington Post, adding: “She’s a very humble person but she has a very powerful voice.”
The pastor said he wasn’t surprised by the social media response.
“I think what I’ve always thought: She has a phenomenal voice, but she also has a gift that the world needs to experience,” Griffin said. “She has a voice of healing that they need to hear.”
He added: “She’s not ordinary. She’s extraordinary.”
On Monday, Swain posted a message on her personal Facebook page, thanking people for the support.
“I am so wonderfully overwhelmed by the love and support shown by millions of people all over the nation and world,” she wrote. “I love you all and have official Facebook, Twitter, and Instagram pages for you to follow and continue to show your love … it means so much … look forward to hearing from all of you!”
She told news organizations that the response to her performance has been “overwhelming.”
“I’m in complete shock right now,” she told the Tallahassee Democrat. “We pray that great opportunities touch more lives in this way through music. I’m hoping that it will open up floodgates so we can do great things, for myself and others.
“If I can do this with the gift that God gave me to touch more lives, then that is what I want to do.”
To “Inside Edition,” she said, “I’m so proud that I am able to be a representative of my country in that way.”
This story has been updated.