We only perceive time through changes.
However, both stalactite and stalagmite in caverns only grow very slowly.
Limestone stalactites in particular form extremely slowly – usually less than 10 cm every thousand years – and radiometric dating has shown that some are over 190,000 years old.
Here are a couple of photos taken in the limestone caverns of Yunnan, China.
While I am in awe with these formations, I don’t particularly fancy seeing them lit up in multi-colors.
I prefer seeing them in their natural color and state.
retireediary 