Antoni Gaudí, the 'Architect of God,' spent the last 43 years of his life working on the Sagrada Família in Barcelona. He famously blended Gothic and Art Nouveau styles with organic shapes inspired by nature, such as columns that resemble trees and staircases like snail shells. Gaudí knew the cathedral wouldn't be finished in his lifetime and left behind complex 3D models rather than flat blueprints. Construction has continued for over 140 years, funded entirely by private donations and tourism. Modern architects now use aeronautical design software to translate Gaudí's complex geometric visions into reality. When completed, it will be the tallest church building in the world.