San Isidro’s Feast Day is an annual celebration in Madrid that is observed on the 15th of May. The day marks the death of San Isidro; the patron saint of Madrid and the patron saint of peasants and laborers.

San Isidro was a Campesino who was born and raised in Madrid during the 11th century, and was eminent for his magnanimity and benevolence. Since the year 1769, San Isidro’s remains have been kept locked in a tomb in the San Isidro Church, and the only person who has access to the tomb’s master key is the King of Spain.

The festivities commence on the Friday prior to the 15th, and lasting for 9 days – it is considered as the biggest fiesta in Madrid. On the day itself, people traditionally go on a pilgrimage to drink from the holy water of San Isidro’s fountain.