In this 1939 photo, Eric and Margaret Lawrence are sitting inside the tank of something called the 60-inch cyclotron -- a machine invented by their father, Ernest Lawrence. The cyclotron is a unique circular particle accelerator, which Lawrence himself referred to as a "proton merry-go-round." In reality, the cyclotron specialized in smashing atoms. Fun facts: this cyclotron contains a magnet that weighs 220 tons, and experiments conducted on this very machine led to the discovery of plutonium and Nobel Prizes for researchers Glenn Seaborg and Melvin Calvin. Ernest Lawrence passed away in 1958 -- just 23 days later, the Regents of the University of California voted to rename two of the university's nuclear research sites: Lawrence Livermore and Lawrence Berkeley Laboratories. | Photo courtesy of Lawrence Berkeley National Laboratory.