Roof of the Sagrada Familia, Antoni Gaudí (1852–1926), architect. Barcelona, Catalonia. The columns of the interior are a unique Gaudí design. Besides branching to support their load, their ever-changing surfaces are the result of the intersection of various geometric forms. The simplest example is that of a square base evolving into an octagon as the column rises, then a sixteen-sided form, and eventually to a circle. Although incomplete, the church is a UNESCO World Heritage Site.