The large hall of Zurich's main station from 1871, today a large square, then with 6 head tracks. In 1902, the tracks were shortened for the first time and in 1930 they disappeared completely from this hall, were extended to the front station side and widened to 16 tracks. On the right is the artwork “L' ange protecteur” (Guardian Angel) by Niki de Saint Phalle. In the background, “The Philosophical Egg” by Mario Merz on the glass wall of the western end of the hall, covering an area of 330 m². The sculpture consists of spiral-shaped red neon tubes, free-hanging animal figures and glowing blue numbers, the latter representing the first numbers in the Fibonacci sequence.