On Sunday, which was the feast day for Saint Martin, some 2,500 people went to Palma Cathedral, as they do on 11 November every year, to witness the Cathedral's "Eight", the Fiesta of Light. At around half eight in the morning, the "magical" effect was at its strongest.

Palma Cathedral's eastern rose window is the largest of Gothic design anywhere in the world. Known as the Gothic eye, it is almost 14 metres in diameter with 24 triangles and 1236 glass pieces. On two days a year, prior to and after the Winter Solstice, the positioning of the window allows morning sunlight to pass through the giant eastern window and form a reflection below its smaller western counterpart.

This is what happened on Sunday as it happens every year, so long as the sky is clear and the morning sun is bright. It will occur again on Candlemas, 2 February, the same number of days after the Solstice as yesterday's event was before it. On the Solstice itself, the phenomenon is different in that the alignment of the two windows allows the sun to enter the eastern window and pass through the western window and form an impression of the Cathedral being illuminated from inside.

This remarkable light show doesn't happen by accident. It is the result of mathematical design from centuries ago which creates the appearance of the figure 8 being formed by the "double rosette" of the western window and the reflected eastern window. And so, from around 8 in the morning, the 8 is created, which means a union, that of the material and the spiritual worlds.