How were the people of the Harappan civilization unique compared to those of most other ancient civilizations

Burials found from Harappa and Mohenjo-Daro are simplistic andcontain few material goods, unlike other civilizations which builtmassive monuments and buried riches in their tombs. The Harappapeople did not have social classes, no rulers or nobility, and noevidence has been found of military activity although the citieswere fortified.