There is nothing more beautiful to see and appreciate than glow worms in their natural environment on a dark night. I have seen them in large numbers in caves and also in a disused railway tunnel and they were quite spectacular.
But last year, while camping, we saw some in a forest environment for the first time and they were no less captivating.
There is something quite magical about an insect that can make itself glow through bioluminescence.
Some fungi (toadstools) are also able to glow in the dark. I have never seen any of these, but they are on my list of things I need to check out sometime!