A waterfall in Antarctica runs blood-red from microbes trapped a million years ago

Blood Falls seeps from beneath Taylor Glacier in Antarctica, stained deep red by iron-rich brine that oxidizes on contact with air. The water comes from a pocket of ancient seawater sealed under the ice for over a million years, in total darkness and without oxygen. Microbes trapped inside still survive there, breathing iron and sulfate instead of oxygen.

— Wikipedia contributors, Blood Falls — Subglacial microbial ecosystem, Taylor Glacier