Maps via Per Square Mile
Here's a pretty cut and dry and terrifying graphic to take in. This rendering shows "how much space the world’s population of 6.9 billion would need if it were as dense as certain cities." So if everyone lived like New Yorkers, the entire population could fit into Texas! Comparatively, if we lived like Parisians (see map below), we'd all be able to fit into 128,000 square miles (or Arkansas, Louisiana, and Mississippi). Let's just not compare living space square-footage, okay?
[Per Square Mile via Infrastructurist]