Spanish National Police officers stand guard around Plaza Mayor (central square) in downtown Palma de Mallorca August 9, 2009. A small bomb went off in the central square of Palma de Mallorca, Spain on Sunday, taking the number of explosions in the Spanish island to three. The explosions followed a phone warning made in the name of Basque separatist group ETA, the website of Spanish newspaper El Mundo reported. REUTERS/Dani Cardona (SPAIN POLITICS CONFLICT)