Ringed by six-foot sheets of bulletproof glass and a sellout crowd, radio-controlled gladiators battle to the mechanical death. At Robot Wars, a two-day-long competition in San Francisco, the crowd roars to the near-constant shriek of metal, the crash of flying parts, and the thunderous beat of techno music. After a series of one-on-one matches, losers and winners alike duke it out in a final death-match called a Melee. California, USA