Four genres (documentaries, news articles, fictional excerpts and movies), six continents (separating North from South America), six social sciences (sociology, anthropology, geography, politics, economics, psychology) and six humanities (history, literature, linguistics, religion, art, philosophy) for a total of twelve modules, twenty-four lectures (each centered on a different theorist) and forty-eight different underground destinations, but only one fundamental question: how can global subterranean communities from both our non-fictional past and our fictional future remain sustainable? Explore some of our world's most intricate cave, mine, subway, tunnel and bunker systems, and discover how woefully insufficient our currently UN-driven model of sustainability continues to be, despite our seemingly well-intentioned efforts at balancing our environment between its social and economic pressures.