Largely maligned by porteÃ±os, the Plaza Miserere, often called Plaza Once, is not for the faint of heart. A major transportation hub in the middle of the chaotic Once neighborhood, an eternal shroud of diesel exhaust accompanies the constant movement. Vendors, prostitutes and evangelists preaching the apocalypse mix with the working class coming and going on the daily grind. It's not advisable to go at night, but during the day, the plaza can expose a side of life in B.A. rarely seen and provide some of the city's best people watching. Just a block away are the remains of the Cromagnon nightclub where a tragic December 2004 blaze left 195 youth dead. The street has been cut off. The survivors and parents of the victims have converted the northwestern end of the plaza into a shrine for the dead. A huge, blazing mural covers the entire corner.