The miracle reportedly occurred in 1906 in Tumaco, Colombia.
At the start of the 20th century a great undersea earthquake shook the Pacific Ocean and casued a tsunami that devastated the shorelines of many cities. However, according to the inhabitants of Tumaco, Colombia, a huge wave was pushed back when the local priest processed out with the Blessed Sacrament.
When the people of Tumaco felt the ground shake on the morning of January 31, 1906, they immediately went to their parish priest, Fr. Gerardo Larrondo. The local inhabitants begged their pastor to perform a Eucharistic procession that would invoke God’s aid to fight back the tsunami wave that threatened the very existence of their city.
The people could see the giant wave approaching the city and so Fr. Larrondo gathered up his courage and with the Holy Eucharist placed in a monstrance, processed head-on towards the wave. He said to the people,
“Let us go, my people. Let us go toward the beach, and may God have pity on us.”
Bravely, Fr. Larrondo approached the wave and made the sign of the cross with the Eucharist — and almost immediately the wave receded and turned back.
At the sight of the wave receding everyone shouted loudly, “Miracle, miracle!” It appeared to the people that the hand of God stayed the destructive force of the tsunami and spared the people because of their firm faith in the power of the Eucharist.
Word spread about the apparent miracle and the people of the city rejoiced and thanked God for having mercy on them in their need.
Source: aleteia
