Like the Barbican, it’s a bleak canvas-colored slab architects don’t know quite how to fix. It was conceived as a postwar pick-me-up, but age was not kind; despite a peerless Thames location, it’s got a reputation as a forbidding architectural scowl that looks more like a pile of sidewalk curbs than an artistic capitol. It’s perkier on the inside. Some 1,000 programs a year go down here at its three concert venues as well as in its huge central hall, which has a cafe and is open to everybody. Dance, classical and contemporary music, the London Jazz Festival, and films fill the bill, which is prolific if self-important. Don’t miss the Undercroft, the hideous concrete negative space under the building along the Thames. When the Centre went up, this area was thought to be useless, so skateboarders and street artists claimed the architectural mistake. Recently, landlords tried to evict them for shops, but too late—the skaters proved too beloved.