Cities often feel like dense and crowded places, and it is hard to imagine everyone on Earth living in urban environments let alone a single city or even (yes, it’s possible) one gigantic megastructure. In a series of videos, filmmaker Joseph Pisenti asks: what if everyone lived in one city? Then he takes it further with: what if everyone lived in just one building?

It sounds like an absurd proposition, but our planet’s population of billions could, in fact, but contained in a relatively small amount of space if needed (perhaps in case of a worldwide evacuation to space?). Images of single cities in the videos show places that already have populations in a single frame larger than countries like, say, Australia have spread across an entire continent.

A few billion cubic meters in a structure set on, say, Manhattan, could uncomfortably house the human race. It would be twice the height on the world’s largest building, but we would fit if we had to.

As the video series unfolds, its creator gets increasingly realistic with respect to actual needs for people beyond simply space to exist, imagining a world where we all could actually live on a small part of South America. Hopefully, of course, it will never come to this, but as sea levels rise it’s good to know we have options (and fun to engage in these thought experiments, regardless). By the time you finish watching this series, however, you may find you would rather simply escape it all: