In the usual explanation, the leaves fade, turning yellow in October. Eventually the leaves die, falling off of the trees. Hence, we often call the season "fall." Biologically speaking ... and purple ...

Check out our fall foliage guide to see where and when to spot peak autumn colors near you. Chlorophyll is what makes leaves ...

Every autumn we revel in the beauty of the fall colors. The mixture of red, purple, orange and yellow is the result of chemical processes that take place in the tree as the seasons change from summer ...

The key to planning fall foliage trips and tours, though, is nailing your timing, especially if you want to sync your leaf-peeping trip ... A vibrant autumn sunset in the Great Smoky Mountains.