The phenomenon has been hailed as a miracle, prompting an investigation by church officials.
Footage of the phenomenon, which worshippers have described as a 'miracle', was recently shared online.
The pontiff's intervention came in response to the case of a woman who is under investigation for allegedly faking 'miracles'.
A chalk drawing of the Virgin Mary has mysteriously reappeared 13 years after it had faded away.
Hundreds of people have been flocking to Argentina to witness what some are calling a modern miracle.
The Vatican is set to rule on the validity of a long history of Virgin Mary sightings in Bosnia.
A luminescent statue of the Virgin Mary has been attracting huge crowds of people on a daily basis.
Crowds of people have flocked to a small town in Israel to catch a glimpse of the weeping statue.