Why Did Ancient Civilizations Build Such Huge Monuments?

The “Dialogue of Civilizations” conference in Guatemala brought together archaeologists studying five ancient cultures to discuss their similarities and differences and what they can tell us about human society as a whole. You can still be a part of the conversation, commenting on this post or tweeting using #5Civilizations.
On the final day of the conference, after two days of individual presentations on ancient China, the Indus Valley, Mesopotamia, Egypt, and the Maya, all the presenters and hosts sat together on stage to discuss the nature of civilization and what we can apply today from the lessons of yesterday, or as the tagline for the Dialogue put it, how to view “the past as a window to the future.” Two days later, sitting on top of Temple IV in Tikal, looking out over the city’s ruins and miles and miles of jungle canopy, the group engaged in another conversation, centered around the collapse of civilizations.
Pulling from both of those, and the experience of recapping the presentations in these blog posts, here are the main questions and themes that seemed to arise from the Dialogue. Leaving the conference there was a distinct feeling that this was simply the beginning of the conversation. Keep it going in the comments below.

 http://newswatch.nationalgeographic.com/2013/05/01/the-ancient-past-as-a-window-to-the-future-part-2-of-3/