Courtesy of a link at Dark Roasted Blend, I found these video clips on the construction of vaulted brick roofs in the Catalan region of Spain. I find it remarkable how the curved structure allows the bricks to support each other, even when the roof isn't complete. The second video clip has closed captioning, so if you turn it on, you can read English subtitles of the Spanish conversation.
I love the speed and ease with which the bricklayers work. I wonder how long it took for them to develop such nonchalant familiarity with the technique? And I wonder how old it is? It may have been in use for centuries.