If life beyond Earth is anything like life as we know it, it’ll find a way to populate even the most improbable landscapes. Here, volcanic lakes, acid pools, desiccated basins, and subterranean caverns are no match for biology. On Mars, or the icy moon Europa? Someday, we’ll know the answer.

To really learn about how life emerges, evolves, and flourishes‚ and to improve our chances of detecting it elsewhere in the solar system—scientists look for life in Earth’s harshest environments. That means going to the extremes—to the hottest, darkest, driest, most acidic, saltiest places on the planet—and seeing what’s there.