Art can often be found in the most unlikely places, a famous prison being one of them.

In the 1950s, a 20-something Mexican-American artist named Alfredo Santos created six large sepia-toned murals on the walls of San Quentin State Prison, near San Francisco. Each depicts a part of California’s history, and progress in style from conservative and textbook-like in appearance, to more bold, whimsical and playful in the later works.

Read more about the murals and Santos in the International Herald Tribune.

Or, explore the details of each mural in this interactive slideshow of the murals in the New York Times.