Any non-mason who has ever tried to lay brick can only marvel at the skill that it takes to create those straight, even rows with perfectly even grout joints—and that's building a vertical wall where gravity keeps everything in its place. But now try to set the brick in place over your head as you create a vaulted ceiling. And here's the kicker: It's just you, your trowel and your tub of mortar—no forms or supports to keep gravity at bay while the mortar hardens, not even a measuring tape. Watch this video as these incredibly skilled Catalan masons (from Catalunya, a region of Spain) lay-up layer after layer of brick to create intricately detailed vaulted ceilings using just a trowel and a bit of magic.