Emmaus High School Chorale has a reputation for bursting into song pretty much anywhere. But when they decided to spontaneously sing John Lennon’s “Imagine” on a boat in Boston Harbor, their song ended up reaching tens of thousands more people than they ever dreamed.

A little over a week ago, the chorale went on a three-day trip to Boston combining concerts and touring. Among their plans was to perform at Old South Meeting House and at Old North Church, two historic sites in Boston.

But on their first evening, the students took a cruise of Boston Harbor when they decided to perform an impromptu rendition of “Imagine.”

“We all decided we really wanted to sing,” student Gabe Kleis said. “It just felt right. The sun was setting. It was the weekend of the anniversary of the Boston Marathon bombing. That song just means so much to all of us and it’s a beautiful piece of music.”

Chorale Director Rita Cortez said the chorale often sings spontaneously at restaurants or while sightseeing. She said “Imagine” is part of the chorale’s repertoire for this year and they sang it at the winter concert. She said there were no other tourists on the boat.

“It was a charter boat, so it was just us,” Cortez said. “Everyone said ‘let’s sing.’ It’s my favorite kind of singing, when we are just singing for ourselves.”

As the students’ harmonies rose over Boston Harbor, several parents who were chaperoning, pulled out their phones to record the performance, including Eliana Ordonez, mother of student Sebastian Mora.

Ordonez’s video was posted on the Emmaus Chorale Facebook page for parents to share, when to everyone’s surprise it started racking up hundreds of views and shares. Viewers posted accolades from “amazing” to “it brought tears to my eyes” and by the third day the video had more than 100,000 views.

Newspapers, television stations and even a radio station in Minnesota wanted to do stories about the video.

“I was pretty much blown away,” Cortez said. “I still can’t believe this is happening. It was just us having fun singing a song we love. It’s just what we do.”

The video has drawn lots of attention to the chorale Facebook page which has more than tripled its followers and increased views on other videos. But none has attracted as much attention as the “Imagine” video which now has more than 150,000 views and has been shared more than 2,600 times.

“I never thought we’d get this many views and compliments,” Kleis, of Lower Macungie Township, said. “I love it. It’s great to see the chorale recognized.”

The chorale is an auditioned a cappella choir made up of 72 students which recently performed at St. Patrick’s Cathedral and Carnegie Hall and also has sung at Notre Dame Cathedral in Paris and the Vatican in Rome.