Nightlights can show us where people live and how that can be influenced by the landscape.
In this 2016 composite image of Iceland, the capital, Reykjavík, is the large, bright area that clearly stands out in the southwest. This city is home to almost half of the country's population, with the remainder living in smaller, urban areas mostly near the coast.
The interior is rugged, high in elevation, sparsely vegetated -- and cold! Sprinkled with volcanoes, ice caps and hot springs, it's a nice place to visit, but nightlights show us not too many people want to live there.