Yes, only the Czechs explored cubism in architecture. (Don’t even think about the Einstein Tower) This avant-garde art movement was active mostly in Prague from 1910 to 1914.
Members of this movement realized the epochal significance of the Cubism of Pablo Picasso and Georges Braque and attempted to extract its components for their own work in all branches of artistic creativity - sculpture, painting, applied arts and architecture. The most notable participants in this movement were the architects Pavel Janák, Josef Gočár, Vlastislav Hofman and Josef Chochol. A major division in Czech architecture occurred in 1911 when many young avant-garde artists from Jan Kotĕra and his circle divorced themselves from the Mánes Association. These younger architects were more idealistic in their outlook and criticized the strict rationalism of their forebears, Otto Wagner and Kotĕra. Janák, Gočár, and Hofman founded the group Skupina výtvarných umĕlců (Group of Plastic Artists) and established a journal for the group, Umĕlecký mĕsíčník (Artistic Monthly).After Czechoslovakia's founding in 1918, architectural Czech Cubism gradually developed into Czech Rondocubism, which was more decorative, as it was influenced by traditional folk ornaments to celebrate the revival of Czech national independence.
