High-rise construction downtown was largely on a decades-long hiatus until about five years ago, when a boom started that has already resulted in a number of conspicuous additions to the skyline. The newest on the block is Block 162, on 15th Street between California and Welton streets. It's the structure that looks like it's coming unzipped at the top, where the curtain walls are theatrically canted out; this flourish gives the tower a distinctive profile that's visible for miles. Closer up, the detailing perfectly integrates with the clean yet complex overall form of the building. The tower is thirty stories, with a podium that houses retail and lobby space on the ground floor, then nine levels of parking before the partly open-air Sky Terrace. From there on, the tower is all office space — and thanks to a remarkable feat of engineering, none of these office floors have internal columns. Block 162 was designed by Gensler, an internationally renowned architectural firm, with Raffael Scasserra serving as design director, overseeing a large team. Despite its extremely prosaic name, Block 162 is downright poetic.