A 10-alarm blaze erupted Saturday afternoon in a dense Cambridge neighborhood, destroying or damaging at least 11 buildings, and displacing at least 60 people in a conflagration that Fire Chief Gerald Reardon described as looking like a "ball of fire" in war zones. "This looks almost like a third-world country after a bombing," Reardon told reporters Saturday night. At least one building collapsed before the fire was contained around 8 p.m., authorities said. Authorities were alerted just before 3 p.m. as flames began to consume a three-family home that was undergoing renovations on Berkshire Street in East Cambridge, officials said.