At White Sands National Park in New Mexico, archaeologists identified 20,000-year-old human footprints ... The team began ...

The most recent period of glaciation, which many people think of as the "Ice Age", was at its height approximately 20,000 years ago. Although the exact causes for ice ages, and the glacial cycles ...

Peter Hilz / Hollandse Hoogte / Redux As you contemplate the likelihood of sea level rise, consider that just 20,000 years ago—a snap of the fingers in geologic time and well within the span of ...