Arion Hall, once home to the Arion Singing Society, is one of many remnants of Bushwick's once-thriving German population. The building sits on Arion Street (formerly Wall Street), between Broadway and Bushwick Avenue/Beaver Street. While the building today is no match for its past glory, its recent renovation as the Opera Lofts is a vast improvement over the sorry state it was only a few years ago (click down to the end of the page).The small Second Empire to the left of Arion Hall is gone - only its ghost remains. The two buildings to the right of Arion survive, enveloped in artificial siding. Still, its apparent that many of the features of these buildings survive.
For more about the Opera House Loft conversion, see this thread at Brownstoner (prompted by a lovely mystery image of the building's pressed-metal cornice, complete with lyre).