Greenland insists it’s not for sale, despite President Donald Trump musing about buying it. But just how much could the world’s largest island be worth to America?

Any price tag on Greenland would depend on how desperately the United States wants it and why, and Trump’s motivations are unclear.

If history is any guide, the autonomous Danish territory is worth at least $1 billion. In 1946, the United States offered Denmark $100 million in gold to buy Greenland, according to documents in the US National Archives. That’s equivalent to $1.3 billion today, taking inflation into account.