In 1911, he traveled again with his friend August Klipstein for five months; this time he journeyed to the Balkans and visited Serbia, Bulgaria, Turkey, Greece, as well as Pompeii and Rome, filling nearly 80 sketchbooks with renderings of what he saw—including many sketches of the Parthenon, whose forms he would later praise in his work "Vers une architecture" (1923). He spoke of what he saw during this trip in many of his books, and it was the subject of his last book, "Le Voyage d'Orient".