After visiting Picasso in his Paris studio, Tatlin returned to Russia and began producing his Relief Constructions (1913-17), a series of sculptures made from an assortment of junk and other "found" materials, in an imitation of similar works by his Spanish host. These Relief Constructions culminated in an extraordinary model for Monument to the Third International (an unfinished wooden prototype), which became a symbol of the Constructivist movement. Exhibited in Petrograd (now St Petersburg) in November 1920 and in Moscow in December 1920. The monument was conceived as a working building, an enormous skeletal apparatus a third higher than the Eiffel Tower, enclosing three rotating volumes intended to house the executive, administrative and propaganda offices of the Comintern. Resembling a huge functioning machine made of iron beams and glass, the tower demonstrated the power of the machine aesthetic as a symbol of revolutionary objectives. Tatlin declared that he was restoring the essential unity of painting, sculpture and architecture, "combining purely artistic forms with utilitarian intentions.. The fruits of this are models which give rise to discoveries serving the creation of a new world and which call upon producers to control the forms of the new everyday life" (Bann, p 14).