Rubel Castle is a monumental folk architecture site nestled in the foothills of Glendora. It was entirely built by hand by Michael Rubel and his "pharmhands" over several decades. Its stone masonry was handcrafted of river rock, recycled materials and an assemblage of the relics and artifacts of Glendora's early agricultural and industrial eras. Michael's innovative use of both natural and cultural materials makes Rubel Castle an exceptionally important masterwork within the context of folk art environments in California.