They were designated a National Historic Landmark in 1990.
Watts Towers of Simon Rodia (The Towers, 1957) Surreal Fantasy Environment
See an article in Curbed LA for updated information about the Towerw - Taking Care of the Watts Towers is a Dangerous Job
Man, Zev Yaroslavsky's bloggers have the scoop on all the good city landmarks (like the Hall of Justice), and now that LACMA's offered to help out with the Watts Towers, they take a trip to visit Virginia Kazor, former historic site curator, and Zuleyma Aguirre, former lead conservator, both of whom worked on the site for about 20 years. Kazor took early retirement this summer amid budget troubles and Aguirre hasn't been able to work in two years, since being hit by a piece of Watts Tower scaffolding in 2008. Obviously taking care of the site is not for the faint of heart. Kazor explains how Simon Rodia built such tenuous towers: "he didn’t weld. He overlapped the pieces, wrapped the overlapped portion with wire to hold them together, and then covered that with chicken wire. Then he took a very dry concrete mix...and he’d press that into the chicken wire. Then he would press into that the decorative elements he had chosen.” The problem is that water seeps in and rusts the metal, which causes cracks. Now "After every Santa Ana wind or winter rainstorm, tile and bits of concrete shower from the structures onto the ground."