In 1967, the Philadelphia Public Schools launched the Parkway Program, widely known as the "school without walls," that enabled young people to have greater freedom and flexibility over what and where they learned. Various community partnerships were formed with businesses, museums, cultural centers and universities, and classes were held in these locations as students became fully immersed in learning in and from their city. The program was so innovative that, in 1970, The New York Times called it "one of the nation's boldest experiments in public education," noting that over ten thousand students applied for only five hundred available slots.

As with many in-system education innovations that begin with great promise and possibility, the Parkway Program eventually became reabsorbed into the larger public school system, losing its experimental edge.

Today, intrepid educators continue to try to make change within the traditional schooling system, but increasingly entrepreneurial teachers and parents are working outside the system to create innovative, accessible K-12 learning models that push beyond the four walls of a conventional classroom—literally and figuratively.

One such program is Revolution School, a private, accredited high school located in a downtown office building in Philadelphia that draws students from more than 25 zip codes across the city. "Zip code diversity is really important to us," said Gina Moore, who founded Revolution School and hosts it within her investment advisory firm's Center City office building. The school opened in 2019 with a small freshman class and today has 31 students in ninth through twelfth grades, with grade-mixing a common feature.

According to Moore, only five students pay the full $25,000 tuition, which is almost half that of traditional, secular private high schools in Philadelphia and comparable to the annual per pupil expenditure of the Philadelphia Public Schools. Most students pay nearer to the $5,000 lower rung of the tuition scale, with several students further off-setting the cost through private scholarship-granting organizations.