lower stairway, below the spiral steps, leads through the tower to
the fourth floor. This journey gives you a good look at the interior
blue tinted windows of the dome, left, and the exterior tower windows,
right. In the center photo you can see how the exterior windows allow
light from the outside to enter and shine through the opposite dome
windows. When you look up at the dome windows from the rotunda, You
are seeing the outside light penetrating the blue tinted glass.