Greek philosopher and mathematician Pythagoras developed a theory of the musical harmony of the universe. He imagined that planets and celestial bodies, while moving along their orbits, create music of the spheres, which echoes throughout the universe, and he called it musica mundana. It is the title of an art and science project, that is, a multimedia concert, with which the Academy of Music, in cooperation with the Academy of Dramatic Art, the Academy of Fine Arts, Zagreb University of Applied Sciences and the School of Design of the Faculty of Architecture, University of Zagreb, wishes to mark International Earth Day on 22 April and make its artistic contribution to raising awareness on the importance of preserving our planet. A number of lectures on the universe and Planet Earth will end with the concert within the Saturday at Lisinski cycle. Besides Hymn to the Earth by J. Sibelius, the programme will include G. Holst’s The Planets, an orchestral suite, in which the composer has presented seven planets of the Solar System and brought the music of spheres and the harmony of the universe to Earth, capturing them for posterity. The Symphony Orchestra and the Music Academy Choir will be conducted by one of the leading young French conductors, Maestro Quentin Hindley.