Cleveland has a distressing penchant for ripping down distinctive vestiges of its past and replacing them — if they're replaced at all — with blandly anonymous construction. But when the subway that carried commuters across the Cuyahoga to the near West Side of town closed in the early 1950s, there was no way to eliminate the deck on the underbelly of the Detroit-Superior Bridge that carried these trains; it was simply sealed off. Recently, it's been opened twice a year — on Memorial Day and Labor Day weekends — for self-guided pedestrian tours. Then, last September, the folks behind the Ingenuity Fest staged a mini-arts festival there, tucking dancers, art exhibits, and opera singers into its nooks and crannies. This September, the whole Ingenuity Festival moved there, with the tracks and tiled passenger areas providing performance spaces and the open sides offering stunning vistas of the river and downtown — complete with a man-made waterfall from the bridge deck to the Cuyahoga. Drivers passing overhead surely had no clue of the celebration unfolding below.