|The Rubel Castle Historic District is significant under Criterion A at the local level of significance for its association with the local citrus industry, which played a crucial role in the development of the area in the late nineteenth and early twentieth centuries. The Packing House and other citrus-related buildings remaining on the property are rare, remnant examples of citrus facilities that once dominated the landscape in this area. The period of significance under Criterion A is 1910-1949, representing the construction of the irrigation reservoir on the property, through the closure of the property as a working citrus ranch. The Rubel Castle Historic District is significant under Criterion C at the local level of significance as a unique, rare, and exceptional example of a folk art environment. 1 Typically these environments reflect the idiosyncratic visions of singular creators working with obsessive consistency over a period of years, during which time intuition replaces blueprints or formal planning toward the rebuilding process.2 The architect, builder , engineer, and resident of the castle, Michael Clarke Rubel, had no formal training in architecture, construction, or art, and no formal designs for the castle. Although Rubel held a job as a school bus driver, his primary occupation throughout his life was constructing the castle, which also served as his residence until a few years prior to his death in 2007. The result is a monumental folk art environment created by thousands of tons of alluvial boulders from nearby washes of the San Gabriel Mountains , and thousands of recycled and found objects . The Castle's recycled objects include everything from small, everyday household items to industrial-scale objects and remnants of the early agricultural and industrial development of the San Gabriel Valley. The Castle possesses high artistic value and embodies the drstinctive characteristics of handcrafted stone masonry, as seen in its central walls, buildings, and towers . The period of significance under Criterion C is 1959, when Michael Rubel acquired the property, through 1986, when the construction of the last component of the Castle was complete. Although it was completed fewer than 50 years ago , the Rubel Castle Historic District meets Criterion Consideration G for exceptional importance. It is a rare, monumental example of a folk art environment that has been celebrated nationally since the 1970s . It is one of Glendora's most important and visited landmarks. As Michael Rubel began work on the Castle, it quickly became a community project, in which Rubel's network of friends and associates, as well as Glendoran residents, contributed materials, equipment, labor, or leads on available objects and materials. The Rubel Castle Historic District reflects the characteristics identified for significant folk art environments in the 1978 Thematic Nomination for Twentieth-Century Folk Art Environments in California.