A man wearing a mask waits to take part in a flash mob named "Halloween bike ride" before touring around the city in Madrid, Tuesday, Oct. 31, 2012. (AP Photo/Daniel Ochoa de Olza)

Photo by: Daniel Ochoa de Olza

A man wearing a mask waits to take part in a flash mob named "Halloween bike ride" before touring around the city in Madrid, Tuesday, Oct. 31, 2012. (AP Photo/Daniel Ochoa de Olza)