The image directs to a religious procession that takes place on Holy Thursday in the Latin Mass tradition. Holy Thursday is the Thursday before Easter Sunday and commemorates the Last Supper of Jesus Christ with his disciples.
In the Latin Mass tradition, the Holy Thursday procession is a solemn and elaborate ceremony where the Blessed Sacrament (the consecrated bread and wine that Catholics believe to be the body and blood of Jesus Christ) is carried in a monstrance (a vessel designed to display the consecrated host) in a procession around the church or outside.
The procession is often accompanied by hymns and prayers, and it symbolizes Jesus' journey to the Garden of Gethsemane after the Last Supper, where he prayed before his arrest and crucifixion. The procession is typically led by a priest or bishop, and it is an important part of the Holy Week observances in the Latin Mass tradition.