At one point in the cavern tour Dave turned out his spotlight and activated a colored light show. Although beautiful the light levels were so low the shutter speed fell far below the range for shooting hand-held even with image stabilization. Of course since we were in a boat sitting on the water a tripod was completely out of the question. This image was shot with a 45mm focal length, F4, 1/3 shutter speed.
As the red light played across the columns the scene brightened enough for a 1/4 second shutter speed
And 1/6 second for the blue light shot
First opened for the public in 1885 Penn's Cave has attracted visitors for 125 years and is still going strong.