Locati reached the peak of his professional career in 1906, when he was in charge of the general artistic direction of the section set up at the Parco Sempione of the great Milan International Exhibition, dedicated to the opening of the new Simplon railway tunnel. For the fair he designed the main entrance with an elliptical configuration with the reproduction of the two entrances to the tunnel, some pavilions, the entrance and pavilion of the National Exhibition of Fine Arts and the Aquarium building, in which the references to the Vienna Secession are clearly evident.