Having toured the ruins of the Egyptian civilization in Cairo, Mayan in Guatemala/Mexico, Inca in Peru, what intrigues me about the Indus Valley civilization is that it was prosperous, peace loving AND egalitarian. I don't believe there is other precidence of these elements in unison being maintained over millenia. Clearly this is something worth researching to find clues of how to create sustainability in today's world.
Evolution
Questions about the adaptation and gradual progression over time or evolution of culture in the ancient Indus Valley civilization.