That grainy tangle of colors is real brain tissue, mapped in more detail than any human brain sample ever has been. The sample came from a woman's temporal lobe, removed during surgery to treat her epilepsy, and donated for research afterward. A team from Google Research and Jeff Lichtman's lab at Harvard sliced it into roughly 5,000 wafer-thin sections, imaged each one with an electron microscope, then used machine learning to digitally stitch everything back into one continuous 3D reconstruction. No human could trace this by hand, the resulting dataset alone runs to 1.4 petabytes, more storage than most people will use in a lifetime. Inside that single cubic millimeter, roughly one millionth of an entire human brain, the team counted about 57,000 individual cells, nearly 150 million synapses connecting them, and 230 millimeters of blood vessels threading through the tissue. The colors in images like this one aren't decorative, they're how researchers visually separate individual neurons and cell types from the tangle around them so they can trace each one's path. The map turned up some genuine surprises too. Most neuron pairs connect through just a couple of synapses, but researchers found rare pairs linked by up to 50 connections at once. They also spotted neurons whose branches curl around and knot into themselves, something nobody had documented before, along with pairs of neurons that turned out to be near perfect mirror images of each other. Knowing this level of detail exists for just one millionth of a brain, how far off do you think a full human connectome actually is?