One of the most iconic and enduring human structures ever built, Barcelona's La Sagrada Familia is an architectural project conceived by Antoni Gaudí in the late 19th century. More than 125 years after construction began, the basilica still remains unfinished. This documentary considers Gaudí's vision and the continuing work of countless laborers, artisans, designers and architects as they strive to complete the colossal project while delving into the mysterious process of artistic creation.