The founder of Khan Academy built the ultimate school for kids to work and play together - take a look inside

Sal Khan is probably best known for launching $4, the free online learning platform that covers everything from art to history to computer programming.

But Khan is also leading the charge on another learning revolution: flexible learning spaces.

Originally founded as an all-ages school in 2014 in Mountain View, California, Khan debuted for the 2017-2018 school year the brand new $4 for high school students. Designed and built by the architecture firm Kurani, the school blends traditional classroom learning with student-led projects.

The approach takes a hard left turn from regular schooling, and it could pave the way for schools of the future. Here's what it's like.