In 1953 Joan Miró and Josep Llorens i Artigas worked at Artigas's studio in Gallifa. There they created "firestones" which they exhibited under their joint names, including in 1956 a joint exhibition in New York. The following year the two worked on a mural for the UNESCO headquarters and for the University of Harvard. The tiles that made up the two murals for the UNESCO building were created in Gallifa and Miro supervised their installation in Paris. The murals are called "The Wall of the Sun" and "The Wall of the Moon".
The tiles for Joan Miró's ceramic mural (the Miró Wall were fired in Gallifa and they were then transported 1200 km to the Ludwigshafen museum in Germany. They were placed four to a box so that they could moved down the mountain by mule. After that lorries and the train were used to complete the journey from Catalonia to south western Germany.