Each fall, green leaves transform into the reds, yellows, and oranges of the season. But, why? Here's what to know.

Leaves changing colors is one of the most iconic parts of autumn in the United States. But why do leaves change their color in the first place?

This is the time of year when Nicole Hughes gets constantly distracted by the fall foliage as she drives around North Carolina. "I'm always looking," says Hughes, a biologist at High Point University.