For the first time in almost ninety years, the astronomical domes of Castel Gandolfo's Papal Palace are open to visitors.

These include two functional observatories of the Vatican: the major dome with an 8.5-meter diameter, equipped with a Visual Telescope for observing stars and planets; and the minor dome, with an 8-meter diameter, featuring the Double Astrograph used for photographic surveys of the sky and the position of stars.

Access the observatories via a spiral staircase to the third-floor terrace, which provides views of Lake Albano.