Greenland (both larger) are generally considered to be continental landmasses rather than islands. Three-quarters of Greenland is covered by the only permanent ice sheet outside Antarctica. With a population of about 56,480 (2013), it is the least densely populated territory in the world. About a third of the population live in Nuuk, the capital and largest city. The Arctic Umiaq Line ferry acts as a lifeline for western Greenland, connecting the various cities and settlements. Greenland has been inhabited off and on for at least the last 4,500 years by Arctic peoples whose forebears migrated there from what is now Canada.
Nuuk Airport flying boat, with the aircraft using the waterways of the Nuuk Port as a landing site. In 1962 a PBY Catalina crashed near the port, killing 15 people on board. The tragedy was one of the factors leading to the decision to invest in a helicopter fleet. The Sikorsky S-61N machines—still in use in 2010—proved to be a more reliable mode of transport for the city, providing exclusive service for the Nuuk city for more than a decade—from the purchase date in 1965 until the late 1970s. Even in the later era of the fixed-wing, turboprop plane domination, the S-61N