Unique in Indiana, the Garden of Prayer is a prime architectural example of a European-style grotto established as a site for spiritual meditation and religious devotion. Originally consisting of one room, it contained an altar, guardian angels, and a statue of Jesus Christ where devotees prayed and lit devotion candles. Later, the grotto was expanded to include a second room with a stained glass window and another statue of Jesus where visitors may meditate in silence. In 1941, the Sentinel Angel was placed outside the entrance to the Garden of Prayer as a memorial to the Mack Family. New structures or displays dedicated at Camp Chesterfield frequently became photographic backdrops for special events, and the Sentinel Angel appeared in a photograph of resident mediums taken around the time of its placement.