U.S. President Donald Trump's ambitions around Greenland are rapidly gaining concrete form — that is, evolving from rhetoric into action.

Greenland is 836,000 square miles of largely frozen ground northeast of Canada. So why does the White House say it "should be part of the United States"?

Discussion of the hypothetical sale rapidly encounters imponderables such as how a meaningful price tag could even be established.

Buying and selling countries sounds like the kind of thing that would only happen in a board game. Yet US President Donald Trump is considering making a bid for Greenland, the White House confirmed on Wednesday.

In Greenland, you can get to pretty much anywhere in a matter of minutes," says local resident Alex Amasa Olsen.

Trump doesn’t need to annex Greenland to achieve his goals. But after Venezuela, he revived his threats to seize it, possibly via military force.

President Trump’s interest in acquiring Greenland fits into a long, little-known pattern in U.S. history, since American leaders have long seen Greenland as a strategic asset.

The White House has kept all options for acquiring Greenland on the table, refusing to rule out military action.

Trump’s threat to annex an autonomous part of Denmark has plunged NATO into an unprecedented situation: An alliance based on collective defense now faces the prospect that one member might attack another.