At the highest and lowest latitudes on the planet, sun, atmosphere and magnetism collide to paint the sky in curtains of light. Up north, it's the aurora borealis, or Northern Lights. Down south, it's the aurora australis, or Southern Lights -- near-mirrors, though one is seldom seen.
Auroras themselves are not rare: About 60 to 200 miles (100 to 300 kilometers) above Earth, collisions are lighting up in neon green, occasionally red or pink, rarely purple [source: Tate]. Seeing them from the ground, though, requires certain conditions, namely darkness, clear skies, a particularly active sun and finding oneself in one of the auroral zones.
The two "auroral zones" on Earth appear as ovals over the north and south (magnetic) poles, respectively. Sightings outside these ovals are practically unheard of, and even within them aren't guaranteed. Still, some locations, at some times, are pretty sure bets.
Here, 10 spots with some of the best auroral views in the world. Alaska no doubt comes to mind, so we'll start there, all the way out in Denali.