Greenland has been part of Denmark for 600 years, but that has not stopped the US showing a consistent interest in it.President-elect Donald Trump has made a number of remarks about taking control of Greenland, possibly even using military force to do it – an idea that has sent shockwaves through Nato. He said the US needed Greenland “for national security purposes”, adding he had been told that “for a long time, long before” he ran for president.