When people imagine what the Earth was like in the distant past, they generally think about megalithic stone structures and the artifacts that have been uncovered. However, these creations of ancient civilizations existed in a world that was far different than the world we are familiar with. In order to comprehend why builders made their structures so large and well-fortified, it is necessary to understand the types of lifeforms that once existed, which ancient people would have needed to contend with and fortify against.

Moreover, so that we can understand why the diverse range of megafauna that once existed are now gone, researchers such as ourselves need to study how the Earth's atmosphere was drastically different in the distant past, and what unusual events occurred to cause these ancient species (and the lost societies that built such impressive stone buildings) to suddenly go extinct.