Twice a year, the sun casts an image of the rose window that presides over the main altar in Palma Cathedral on the opposite wall, just under another rose window, the one that decorates the main façade. Thus, for a short period of time, two tangential rosettes can be seen, one made of glass and the other made of light, forming a figure of eight.
Palma Cathedral has the largest original Gothic rose window in the world. The effect happens on November 11th (the Feast of Sant Martin) and February 2nd (the Feast of La Candelaria) each year.
Visit the Cathedral on these days in the morning, at around 08:00-08:30, to witness the effect yourself. Doors open at 07:30 (entrance through Porta de l'Almoina, the eastern gate), free entry.