The spire that will adorn One World Trade Center got hoisted to the building's roof today, though it will be weeks before it's actually installed. Still, today's milestone was treated with the appropriate pomp and circumstance in Manhattan. The 408-foot spire will bring the height of the building—the biggest of four skyscrapers going up at Ground Zero—to the symbolic height of 1,776 feet, reports Reuters. That will make it the tallest building in the US and the third-tallest in the world, notes AP. The 104-story structure is due to open next year.