Fast-growing brain-training app Lumosity has unveiled its brand-new headquarters in San Francisco's South of Market neighborhood.
The 36,000-square-foot office takes up three floors of the historic Pacific Telephone & Telegraph Building, with an entire floor dedicated to social gathering spaces for the company's 340 employees.
The entire office is filled with references to school and learning, like the chalkboard and massive paper clip at the reception desk. 
You can see exposed light bulbs hanging throughout the office, including this bar-inspired dining and games area. 
But the best part of the office has to be this library, which is accessible by a secret, hidden door. 
Stacks of antique books are arranged by color on the shelves, seen here with the door closed. 
There are also several cozy nooks, with leather couches that offer a peaceful spot for employees to get some work done. 
SEE ALSO: Google's New Office In Amsterdam Is Full Of Bikes, Waffles, And Other Wonders
WE'RE ON PINTEREST: Click Here To Follow Us