It is part of the Our Lady of the Angels Monastery in Hanceville, AL, run by the Poor Clare Nuns.
This description from wikipedia says it better than I ever could: "The stone and concrete models are the work of Brother Joseph Zoettl, a Benedictine monk of St. Bernard's, who devoted some 50 years to the project, the last three decades (1932 to 1961) almost without interruption. They incorporate discarded building supplies, bricks, marbles, tiles, pipes, sea shells, marbles, plastic animals, costume jewelry, toilet bowl floats and cold cream jars."
We agreed it is amazing how such a unique gift could be used for God's glory. People travel from all over to see this place. We heard a family speaking Russian and we heard someone else speaking Italian while we were there.