Eucharistic Congress 1926
This is from an article found here--more is found at that link.
The first Eucharistic Congress of the Catholic Church took place in Lille, France in 1881. The 28th Congress was held in Chicago, June 20-24, 1926, the first time it had been hosted in the United States. It was considered the greatest religious gathering in modern times.
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On June 24th, 750,000 people made a pilgrimage in a Eucharistic Procession from Chicago to St. Mary of the Lake in Mundelein. The participants traveled on foot, by auto, bus, and by rail. Shown below is a view of St. Mary of the Lake with the procession being led by Cardinal Bonzano. The Chapel of the Immaculate Conception is at left.
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The village's population swelled from 590 to 750,000, as the faithful and Church religious gathered from around the world at St. Mary of the Lake. Chicago's North Shore Line railroad made history when it transported 250,000 people to the event. Today, a trail on the south side of Route 176 is all that remains of the line that brought people to St. Mary's.
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More is found at the link....
My dad said all he remembered were lots of adults' feet. He was three years old.
There is a link for over a thousand more photos on this site.