Father Matthias Wernerus (1873–1930) constructed his grotto on the grounds of the Holy Ghost Church between 1925 and 1930. His handiwork in stone is dedicated to the unity of two great American ideals—love of God and love of country. These religious and patriotic shrines were constructed without the use of blueprints.

Wernerus used locally found objects and materials solicited from area businesses, and household objects from parishioners such as broken glass, tops of perfume bottles, seashells, and colorful stone. Concrete was inexpensive and readily available.

Grotto building was popular in the early twentieth century, particularly in the Midwest and South. The grotto’s distinct patriotic and religious themes were perhaps intended to show other Americans that devout Catholics could be loyal citizens of the U.S., as most non-Catholic Christians in America at that time believed that Catholics’ first allegiance was to the pope.

Father Wernerus died in 1931, just one year after completing work on the grotto along with many other volunteers. Today it can be visited and experienced in much the same way as it was in 1930.

It is a creation in stone, mortar, and bright colored objects—collected materials from all over the world. These include colored glass; gems; antique heirlooms of pottery or porcelain; stalagmites and stalactites; sea shells; starfish; petrified sea urchins and fossils; a variety of corals; amber glass; agate; quartz; ores such as iron, copper, lead, fool’s gold, rock crystals, onyx, amethyst, and coal; petrified wood; and moss.

There are several shrines in the Grotto garden. Besides the main shrine (which houses the Grotto of the Blessed Virgin), there is a patriotic shrine, the sacramental shrine of the Holy Eucharist, the Sacred Heart shrine, Christ the King shrine, Fatima shrine, and the Stations of the Cross. These shrines are located in a beautiful floral garden area surrounding the Holy Ghost Church.

The word Grotto means an artificial cavern or cave. The entire Grotto is dedicated to the virtues of religion and patriotism.