Five million visitors crowd into St. Patrick's Cathedral in New York each year. Hundreds of thousands annually pay homage to the Blessed Virgin at the National Shrine of the Immaculate Conception in Washington, D.C. But Catholic travelers don't always realize that every state in the Union contains unique shrines, retreat houses, missions and other significant holy places. In 101 Places to Pray Before You Die, you'll discover the unexpected, the somber, the whimsical and the inspiring spots that, at times, are hidden in plain sight.

• Every American has heard of the Battle of the...