The Northern and Southern Lights
The official names for these lights in the sky are the Aurora Borealis (The Northern Lights) and the Aurora Australis (The Southern Lights).
The word "aurora" is used to specifically describe the natural light displays that occur in the Arctic and Antarctic regions.
The light is a result of the "collision of energetic charged particles with atoms on the high altitude atmosphere."
I totally want to see these with my own eyes one day.
The Northern Lights-- Aurora Borealis
Midwestern U.S. at Night With Aurora Borealis (NASA, International Space Station, 09/29/11)
"Aurora Borealis, the colored lights seen in the skies around the North Pole, the Northern Lights, from Bear Lake, Alaska" Photo by Beverly & Pack
The Southern Lights--Aurora Australis
NASA's IMAGE Spacecraft View of Aurora Australis from Space
"aurora australis-Scott Tent" Photo by M1K3Y