A miracle happens every year in Naples, Italy. The dried blood of the Holy Martyr Iannuarius in glass vials becomes liquid and even boils. The event is considered the second most important after the descent of the Holy Fire in Jerusalem, and the memory of the ascetic is honored on May 4.
Saint Iannuarius lived in the 3rd century on the territory of modern Italy and was executed as a result of persecution of the faith around 305. Believers collected and preserved the particles of his blood.
Since then, the relic has been located in the Cathedral of Naples. Usually, a miracle occurs on the saint's memorial day, as well as in December — in memory of the city's salvation from the eruption of Vesuvius in 1631. Sometimes blood thins during natural or man-made disasters.
On the days of the holiday, the cancer with the vials is opened, the dried dark brown mass from it begins to lighten, turns red and sometimes boils. The process can take from a few minutes to several hours. However, incidents have been recorded in which the contents of vials became liquid in a few moments.
In the 20th and 21st centuries, scientists investigated the substance and proved that it contains hemoglobin, which is characteristic of human blood. However, science still cannot explain why blood regularly thins without external influences. The first records of the miracle date back to the 4th century and relate to the ancient chronicles of Naples and church documents.