The world's largest ocean basin is also the oldest. A basin is "a depression, or dip, in the Earth's surface," according to National Geographic. The Pacific Ocean is the largest, deepest and oldest ...

Mars once had sprawling river systems that rivaled major watersheds on Earth, and scientists have now identified the biggest ...

Billions of years ago, it rained on Mars. The water collected in valleys and rivers, filled and spilled over the rims of craters, and was funneled into canyons, perhaps even making its way to a large ...

Across 2.3 million square miles, the Amazon River Basin is the largest drainage basin in the world. Countless streams, rivers and creeks flow from the rainforest to a central river, eventually leading ...

Long before Mars became the cold, dry world we see today, rain once fell across its surface. Water gathered in low-lying valleys and river channels ...