A sharp contrast in nighttime light density distinguishes the sparsely populated Tibetan Plateau—the “Roof of the World”—from the fertile and densely inhabited Indo-Gangetic plain of Northern India and Pakistan. These regions are not only visually distinct from an astronaut’s view; they are physically separated by the Himalayan mountain range. South of the Himalayas, the cities of New Delhi, India, and Lahore, Pakistan, stand out among the network of cities on the plain. On the other side of the Himalayas, tectonic forces have worked for about 50 million years to elevate the Tibetan plateau to an average of 4500 meters (14,764 feet) above sea level. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth.