The red in Blood Falls is iron.

Specifically, it is iron oxide, the same compound that makes rust red and gives the surface of Mars its distinctive colour. When iron is exposed to oxygen, it oxidises, and the resulting iron oxide is a deep, saturated red. The process is chemistry so common and so ancient that you can find examples of it everywhere from old nails left in the rain to the soils of tropical Australia.

What makes Blood Falls extraordinary is not the chemistry itself but where the iron comes from and why it arrives at the surface at all.

Beneath the Taylor Glacier, several kilometres from where the falls emerge, there is a subglacial pool. It formed at least 1.5 million years ago, when ancient seawater became trapped beneath what would eventually become hundreds of metres of ice. Cut off from the surface, the water could not exchange gases with the atmosphere. Over millions of years, bacteria in the sealed environment consumed all the available oxygen. The pool became completely anoxic, meaning it contains no oxygen at all.

Without oxygen, the iron dissolved from the surrounding rock and bedrock accumulated in the water rather than oxidising and settling out as rust. The pool became extraordinarily rich in dissolved iron, brine so salty it remains liquid at temperatures well below freezing, sitting in complete darkness under a glacier, loaded with iron that has never seen air.

When that brine finally reaches the surface, it oxidises immediately. The dissolved iron hits oxygen for what may be the first time in over a million years and turns red on contact. What you see pouring from the glacier is not contamination or biological pigment. It is ancient chemistry completing itself in real time.

Why it comes out at all

For most of its history, the subglacial pool stays where it is. The water is trapped, pressurised, sealed under ice. But the Taylor Glacier is not static. Like all glaciers it moves, grinding slowly across the bedrock below it.

When the ice slides downward, even by millimetres, it creates immense pressure on the pool beneath. When that pressure builds to a critical point, brine forces its way through cracks and fissures in the glacier toward the surface. It travels upward through the ice, emerging from a series of fissures near the glacier's edge, and spills out onto the surface as Blood Falls.

The flow is not constant. It spurts and pauses depending on the movement of the glacier above. Scientists using GPS sensors, time-lapse cameras, and temperature monitors have tracked the relationship between glacial movement and the timing of outflow events, confirming that each episode of Blood Falls is triggered by the ice above pressing down on the ancient brine below.

It is, in a very literal sense, the glacier bleeding.

Life where life should not exist

Perhaps the most remarkable thing about Blood Falls is not the colour or the chemistry. It is what is living inside it.

In 2009, scientists studying the subglacial pool discovered at least 17 distinct types of microorganisms surviving in the brine. These are not organisms that wandered in recently. They have been isolated from the surface for potentially millions of years, evolving in complete darkness, in water with roughly four times the salinity of the ocean, at temperatures around minus five degrees Celsius, with no oxygen and no sunlight.

They survive by using sulphate as a terminal electron acceptor in place of oxygen, a form of metabolism that is vanishingly rare at the surface but appears to work remarkably well in extreme closed environments. The iron that saturates the brine is part of their metabolic cycle. They are, in a very real sense, eating rock chemistry in the dark.

The discovery matters beyond its strangeness. The McMurdo Dry Valleys are considered one of the best analogues on Earth for conditions on other planets, particularly Mars and the subsurface oceans of Jupiter's moon Europa. If life can persist in conditions this extreme, sealed for this long, with this little to work with, the boundaries of where we might expect to find life elsewhere expand considerably.

Blood Falls is not just a geological curiosity. It is a data point in one of the biggest questions in science.

What makes Blood Falls visible from hundreds of metres away, what makes it striking in photographs and astonishing in person, is colour. The red is so vivid against the white of the glacier and the pale grey of the surrounding rock that it reads almost as impossible. It looks wrong. It demands an explanation.

That is exactly what colour does in nature. It carries information. It signals chemistry, biology, process, and history. The red of Blood Falls is not decorative. It is the visible record of a million years of isolation, of iron accumulated in darkness finally meeting oxygen at the surface. A colour produced not by pigment or biology but by physics and time.

At CMY Cubes, the relationship between colour and what it reveals about the physical world is what drives everything we make. The colours you see shifting through our resin are not painted on. They are wavelengths of light being filtered and transmitted, the same physical processes that colour a sunset, a prism, a peacock feather, and a blood-red waterfall at the edge of the world.

Colour is always telling you something. The trick is knowing how to read it.