Stained glass windows date back to the Middle Ages (the year 1000 or so) and the construction of the large Gothic cathedrals of Europe. The windows (and the statuary) were designed to portray Old and New Testament stories to congregations, both rich and poor, well born and peasant, were for the most part illiterate. Monks and scholars (most of whom were monks) were generally the only people who could read and write in those days.
Even after the invention of movable type in the 15th century, and the printing of books in large quantities, reading among the populace did not become common until the 18th and 19th centuries. Churches continued to use stained glass to tell religious stories.
Today, with almost universal literacy in most countries, stained glass continues to be used in the construction of most churches, but the perceptive viewer will note that they no longer tell stories as they did in the past. No doubt the cost of stained glass also has something to do with that. Most new churches include clear glass in their original construction specifications and then as the original debt begins to be paid off, interior decoration and stained glass are added to the building.
Anyhow, all this is preparatory to listing some links of beautiful stained glass found in nearby churches that I ran across on the Flickr photo-sharing website on the Internet today.
The Blessed Mother, St. Joseph and St. John the Evangelist
Our Lady of Knock 1879
Shrine of Our Lady of Guadalupe, La Crosse, Wisc.
Cathedral of St. John the Evangelist in Milwaukee, Wisc.
Gesu Church in Milwaukee, Wisc.
St. Josaphat's Basilica in Milwaukee, Wisc.
Basilica of the National Shrine of Mary, Help of Christians, in Holy Hill, Wisc.
Cathedral of Christ the King in Superior, Wisc.
St. Thomas More Parish (formerly, St. Luke's), St. Paul
The Cathedral and Shrine of St. Paul in St. Paul
Basilica of St. Mary in Minneapolis
And many more regional churches, photos taken or assembled by someone named "Jeff"