Park Güell Porter's Lodge House mosaic roof, Barcelona

The architect Antoni Gaudí spent his long career adding imaginative accents to the Spanish city he called home. Barcelona was historically known as a gritty center for shipping and heavy industry, and Gaudí saw the expansive city as a canvas for his unusual approach to building design. Marked by intricate mosaics and undulating shapes inspired by natural forms, 14 of Gaudí's buildings and complexes now dot the Catalan capital. These include the garden-lined Park Güell (where the pictured pavilion stands at the entry gates) and his magnum opus: the beautifully bizarre Sagrada Familia.