Will Sylvester watches a lot of videos of people telling stories from the heart.

But as he sat, late into the night, watching a reel of footage collected Monday from the inflatable "Truth Booth" near Fenway Park, only one of them made him cry.

“That happens very rarely,” said Sylvester, who is among the creators of the booth, a traveling art experiment that lets passersby enter in privacy, look at the camera and respond to the prompt “The truth is…” any way they want, in two minutes or less.

The story came from an unidentified woman (all the videos are anonymous) who said Opening Day was her first time seeing the Red Sox since her fiancé died of a stroke last year, and shared how happy the experience made her feel.

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According to Sylvester, a New Yorker who is in Boston for the week, the woman also took the time to encourage others to visit the doctor and get regular check-ups.

“I guess I call myself — not a tough guy, well, maybe — but I definitely was like, ‘Oh my gosh. I am tearing up right now. This is really intense. It’s great. It’s powerful and strong,’” he said.

On Monday about 70 people, most of them Sox fans on their way out of the historic stadium, dropped by "The Truth Booth," which is shaped like a giant white thought bubble, Sylvester said.

It was the first of a two-day run at The Verb Hotel on Boylston Street. From Wednesday through Friday the inflatable booth will be at a spot along the North End side of the Rose Kennedy Greenway from noon to 7 p.m.

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Sylvester said he plans to make a compilation video of the best “truths” collected in Boston, possibly by the end of the week.

The Red Sox story that brought tears to the tough guy is a contender for sure, he said.

"The Truth Booth" is a production of an international artist group called the Cause Collective, which has aspirations of bringing the installation to all 50 states. They launched a Kickstarter online fundraiser on Tuesday.