I used to look at maps and think of the land masses as just floating on top of the water like Fred the Weathermans United Kingdom when he'd do the weather on Richard and Judy and jump around on it.

The truth is that land is just the bits that stick up high enough to emerge from the sea. When you look at Greenland it looks like it's floated away from Canada but its actually just that the bit between Canada and Greenland has either sunk or Canada/Greenland his risen.