(CNN) -- Irreverent?
What began as a spontaneous idea and Instagram post has sparked a stream of travelers to send in fun, topless photos -- taken from the back -- to be featured on the social media channels of the Topless Tour, which began as an Instagram project.
Judging from the enthusiastic response and growing number of participants, there's something about posing topless that heightens the feeling of liberation and adventure while traveling.
How it started
The Topless Tour was started two years ago by friends Olivia Edginton, 20, Lydia Buckler, 21, and Ingvild Marstein Olsen, 20, students at Trinity Laban Conservatoire of Music & Dance in London.
After taking an impromptu topless dip in a cold lake in Olsen's hometown in Norway, the three friends wanted to capture the moment of freedom.
"It simply just happened, no planning involved," Edginton wrote in an e-mail.
They continued to travel and post similar photos throughout Europe and New York, all featuring themselves in topless poses against dramatic backgrounds.
Then they called for others to send in their topless photos from around the world.
From Idaho to Cape Town to Thailand, the mildly salacious images poured in.
Among the more amazing submissions: a woman bungee jumping topless in the Swiss Alps.
More to come
The Topless Tour currently has nearly 20,000 followers on Instagram.
That number is increasing quickly as the trio and a growing community continue to document their travels with bare backs.
Although the topless photos come predominantly from women, many men have submitted as well.
"We never imagined it would have such global reach and appreciation," Edginton said. "It was always just something we would hope would catch on, never really thinking it would happen."
For the trio leading the Tour, the best part of the experience has been hearing people's stories from all over the globe, and how the project has helped people "feel themselves again, be proud of who they are and love their beautiful bodies," said Edginton.
"One of our followers recently said these lovely words: 'All that pressure and judging went away. And so did my shirt. I felt free, happy, and me.' "
Correction: We incorrectly described an Instagram post as a woman skydiving, rather than bungee jumping. This has now been fixed.