Some conifer seeds require fire to germinate — heat from wildfires melts the resin sealing their cones.

A bolt of lightning is only about as wide as a thumb — the bright flash makes it appear much wider.

Lightning strikes Earth about 100 times every second.

Most lightning strike victims survive.

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

Humans have a vestigial muscle called the palmaris longus that once helped ancestors climb trees — about 14% of people lack it.

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

There is a river in Colombia called Caño Cristales that turns bright red, yellow, green, and blue — it's called the liquid rainbow.

Trees growing on slopes develop asymmetric root systems and denser wood on the downhill side for stability.