Peter Neff, a glaciologist working in Antarctica, recently posted this video to Twitter of what happens when you drop a chunk of ice down an ice borehole (researchers use the ice cores to learn about historical trends in the ice and climate). 

To be clear, we expected it to sound pretty cool, but the noise the ice makes when it hits the bottom of the borehole is unexpected and really nifty: 

[Peter Neff]​