Trump said he will get Greenland "one way or another". In 1985, Trump was able to force the sale of Mar-a-lago for much less by threatening to ruin the view.
Is there some way he can threaten Greenland (or Denmark) and force the sale?
Here's the full story from Wikipedia:
"Donald Trump initially offered the Post family $15 million, which was rejected. Trump then purchased land between Mar-a-Lago and the ocean from Jack C. Massey, the former owner of KFC, for $2 million,[25] stating he intended to build a home that would block Mar-a-Lago's beach view. This threat caused competing interest in Mar-a-Lago to decline. Trump purchased the property for $7 million in 1985.[26][21] Different sources have put the combined total cost of the purchase at around $10 million.[27][28][29] The minimum acceptable bid had been $20 million, and the interior furnishings were appraised at $8 million.[30]"