Mars wasn't always the barren desert we see today. New research has mapped sixteen massive ancient river systems across the red planet for the first time—and the scale is staggering.

Scientists at the University of Texas at Austin used orbital laser data to trace drainage basins that once carried enormous volumes of water across Mars's surface. These ancient watersheds produced roughly 28,000 cubic kilometers of sediment—evidence of rivers that flowed for potentially millions of years.

But here's the mystery: where did all that water go? Mars was once warm and wet enough to sustain vast river networks, yet today it's a frozen wasteland with an atmosphere 100 times thinner than Earth's.

In this episode, we explore what these newly mapped river systems tell us about Mars's vanished oceans, the catastrophic loss of its magnetic field that stripped away its atmosphere, and the climate collapse that transformed a potentially habitable world into the desolate planet we see today.

The maps also raise tantalizing questions: if Mars had this much flowing water, could it have harbored life? And what can this planetary death teach us about Earth's own fragile climate?

The red planet's rivers are long gone—but their ghosts remain, etched into the landscape, waiting to tell their story.