In 1960 a pavilion for the new clock was built next to the tower to present Zimmer's masterpiece the wonder-clock. (). These wonder-clocks were prepared for the 1935 world exhibition in Brussels; later they were demonstrated in the U.S.. Around one of these dials moves the slowest pointer in the world - its complete revolution will take 25800 years, which corresponds to the period of the precession of the Earth's axis. Subsequently, Zimmer attached to the clocks a mechanical planetarium. The wonder-clocks impressed Albert Einstein, who congratulated Zimmer on the creation of these unusual mechanisms.