This is the interior of the Mary's Grotto.
Our tour guide told us this was the first Grotto which Father Dobberstein made.
You can read more about that under the Origin & Inspiration for the Great Work.
While Christian was standing in the middle of Mary's Grotto. Eyes all aglow and a big smile all over that cute little face. He said; "Grandmother , Baby Jesus even has his arms open to us while He is still in His mothers arms." Then as he looked around and then up to the Dome. "Oh wow, It looks like we are looking up into Heaven and all the angles are watching over us."
With that our guide told us the dome was 30 ft. tall and represents heaven. The angles in the dome are sing

"Holy, Holy, Holy, Lord of Hosts; Heaven & Earth are filled with Your glory. Hosanna in the Highest."

On the next page you will see a photo of the Dome and a Stained Glass Window.
The window was imported from Bavaria. It is when the Angle Gabriel came to Mary.