The Light and Shadow Magic of the Sagrada Familia If you can only visit one attraction in Barcelona, it must be the Sagrada Familia. After more than 100 years of construction, Sagrada Familia has not yet been completed. It is the most spectacular unfinished building in the world and the only building that has been listed as a World Heritage Site. The design of this church still carries the strong natural color of Gaud. There are many elements in the form of animals and plants designed in blue. Especially the use of light in the church is a sigh of Gaudi's genius. In short, every detail of the church is moving. Gaudi said: "The light of the church is just right, not blind." The stained glass of the Sagrada Familia is made up of geometric patterns, creating a Mediterranean atmosphere that is different from traditional religious figures. He once said: "Art must come from nature.