There’s a passage in the Bible that suggests the Nile once turned to blood. But the red ribbon in this image isn’t quite so grizzly, because it actually depicts the vegetation growing around the river.
This satellite image was captured by the European Space Agency’s new Sentinel-3A satellite. Its instruments collect data about the Earth’s oceans, land, ice and atmosphere, collecting energy radiated from Earth’s surface across nine different spectral bands. In this image, red areas indicate the presence of vegetation. Not blood.