The world's deepest cave, Veryovkina in Georgia, descends 2,212 meters below the surface.

Lightning strikes Earth approximately 100 times per second.

Glacier retreat is causing 'peak water' — rivers fed by glaciers will eventually have less water as glaciers disappear.

The average lightning bolt is about 1 inch wide and 5 miles long.

Piranhas are typically timid — mass attacks on humans occur mainly during drought when they're stressed and food is scarce.

A sneeze can travel faster than a Category 1 hurricane.

Lichens are not a single organism — they are a symbiotic partnership between fungi and algae or cyanobacteria.

Lightning can heat air hotter than the surface of the Sun.

Some trees can communicate with each other using underground fungal networks.