Great Smoky Mountains National Park tops a new study ranking the best national parks for an autumn getaway, beating out Acadia and Shenandoah.

Add Yahoo as a preferred source to see more of our stories on Google. For many Americans, colorful fall leaves are one of the best parts of the season. Families plan road trips, visit parks and spend ...

Climate tipping points are critical thresholds that trigger unstoppable shifts to another state. The global climate system is full of teetering tipping points that collectively threaten the climate ...