77.7170°S, 162.2670°E.
Blood Falls is a slow seep of iron-rich brine that emerges from the snout of Taylor Glacier in the McMurdo Dry Valleys of Victoria Land, East Antarctica, staining the ice cliff and the frozen surface of West Lake Bonney a deep rust red. The feature was first described by the Australian geologist Griffith Taylor in 1911 during Robert Falcon Scott's Terra Nova expedition. The brine source is a subglacial reservoir trapped beneath the glacier for an estimated 1.5 to 2 million years; it is extremely cold, three times saltier than seawater, low in oxygen, and supports a chemolithoautotrophic microbial community that respires sulphate by recycling iron, with no light and no atmospheric input. The colour comes from oxidation of dissolved ferrous iron when the brine reaches air.
Blood Falls is one of the few places on Earth that is genuinely studied as an analogue for ice-covered ocean worlds.