In 1942 he converted the circular Arts Pavilion, Trg žrtava fašizma, Zagreb, designed by the sculptor Ivan Meštrović, into a mosque by adding three free-standing minarets around the body of the central cylinder and designing a new interior richly decorated with arabesques. The mosque, a monumental and somewhat bizarre addition to the Central European appearance of its surroundings, was demolished in 1949 for political reasons, and Planić was anathemized because of it.