We went to an a cappella competition starring Facebook and Google employees and it was like 'Pitch Perfect' meets 'The Social Network'

There's nothing like the holiday season to bring people together. That includes the tech elite.

Tuesday, a cappella groups made up of employees from Facebook, Google, Twitter, LinkedIn, Microsoft, Dropbox, Pinterest, and Airbnb united on stage for the third annual Techapella Holiday Concert. The performance, which is free to the public, gives members of Silicon Valley a chance to set aside any industry rivalries and celebrate a common joy.

"We know [singing] isn't part of our job, but it's more or less an extra curricular activity," says Laolee Xiong, a founding member of Facebook's group, The Vocal Network, and an environmental, health, and safety training programs manager. "We're more than software developers and engineers - we love to sing, too." 

Tech Insider went backstage at Techapella to see how the event comes together.