The Arctic and Antarctic have long nights in the winter and long days in the summer. Above the Arctic Circle (66 °N), there is at least one day with no sun– polar night, and one day with no night— midnight sun. This graph shows the length of day through the year for three places in the Arctic: Reykjavik, Iceland, is the only national capital in the Arctic, Murmansk, Russia, is one of the largest cities in the north and finally Alert, Canada, the northernmost inhabited place on Earth. Alert experiences 4 months with the sun below the horizon (polar night) in the winter, and 4 months of midnight sun.
From collection: International Polar Year (IPY) educational posters
Hugo Ahlenius, UNEP/GRID-Arendal