Sagrada Familia, Barcelona, Spain (14/20)

Though it is slowly becoming more famous, the Sagrada Familia remains one of the most unique architectural projects in the world. Designed by Antoni Gaudí, this surreal basilica in Barcelona has been under construction since 1882 and is still unfinished. With its organic shapes, towering spires, and imaginative facades, it’s one of the most extraordinary examples of modernist architecture.