A nighttime view of Tokyo from the International Space Station as it orbited 420 km (261 mi) above the island nation in February 2021. The heart of the city is brightest, with ribbons of lights radiating outward from the center along streets and railways. The regularly spaced bright spots along the ribbons heading out of the downtown area are train stations along public transit routes. The lights of Tokyo are a cooler blue-green color than in many other world cities. The color results from the more widespread use of mercury vapor lighting as opposed to sodium vapor lighting, which produces an orange-yellow light. Photo courtesy of NASA.