|I'm not saying it was ...|
|Xenu was here|
Mohenjo-daro is an archeological site of one of the largest Indus Valley civilizations that thrived around 2000 BCE. Pseudohistorians and proponents of ancient advanced civilizations or extraterrestrial visitations claim that there is evidence that its population was killed off by an atomic bomb explosion around 1500 BCE. The proffered evidence is rife with pseudoscience;
but despite this, so, unsurprisingly, it has featured prominently on the History Channel's show Ancient Aliens.
 Mud brick buildings
One difficulty with the nuclear blast claim at Mohenjo-daro is is immediately apparent when pictures of the dig site are examined. The buildings were made with kiln fired mud bricks. Some of the walls are still 15 feet high. How a mud brick wall withstands a nuclear blast never seems to be addressed.
The primary evidence cited in support of an atomic bomb explosion at Mohenjo-daro is the discovery of a series of bodies throughout the cities. Their presence, it is argued, suggests a single cataclysmic event:
“”when excavations of Harappa and Mohenjo-Daro reached the street level, they discovered skeletons scattered about the cities, many holding hands and sprawling in the streets as if some instant, horrible doom had killed its inhabitants. People were just lying, unburied, in the streets of the city; there seemed no-one available to bury them afterwards.
The actual evidence however, is far different, more subtle and more interesting. The bodies were discovered during excavations between 1922-1931. Scholars have criticized the approach used during the dig period and have stated that the poor methodology makes interpretation difficult. However, even though some of the original excavators interpreted the evidence in a way that suggested the bodies were linked by a single catastrophic event, they took the view that the catastrophe was a war and not a nuclear explosion. 
A total of thirty-seven bodies were found. Although some were found in the same parts of the city, their distribution suggested that many came from different time periods [source needed]. Mohenjo-daro had three major periods: Early, Intermediate and Late. Some of the bodies were clearly Early period and some clearly Late. The two periods are a thousand or more years apart[source needed]. Another key point is that the bodies actually showed clear signs of burial [source needed]. The most infamous group of bodies, as highlighted from the quote above, that were found laying in the middle of the street was actually caused by the fact that the bodies were buried during the later period when the existing buildings had been built over earlier periods. The bodies were buried above a road from a period hundreds of years earlier.
Proponents of the bomb explosion often like to point to the preservation of the bodies, particularly the lack of signs of scavengers as proof that something like a background radiation had to keep animals away. Several important points about this, the first is this is one of the driest and hottest spots on the planet, perfect weather for preservation. The scavenger problem is only a problem for the pseudohistorians who seem unaware that the bodies were actually buried.
Small groups of bodies dating from multiple periods a thousand years apart, with clear signs of burial, and some stratum coincidences, clearly is weak evidence for an atomic explosion. The evidence is also nothing like what is presented on proponent websites or television. An interesting fact though is that this is not the first time that the Mohenjo-daro bodies were the subject of controversy. The original excavators tried to use them as proof that the indo valley civilization was killed by invading hordes of Aryans. Much of the evidence presented showing that the bodies were not due to a single large scale event was elucidated 50 years ago to disprove the invading horde hypothesis.
Beyond the bodies themselves pseudohistorians make a series of claims about radioactivity levels in the area. These claims range from a radioactive dust covering the whole city, to the bodies themselves being "among the most radioactive ever found, on par with those at Hiroshima and Nagasaki." The problem with these claims is that they are so vaguely sourced it's impossible to find the original claims to verify it. Other radioactivity based claims are easier to refute.
For example, those making them might require some education on the concept of radioactive half-life and its operation over a timespan of 3,500 years. That's over 115 half-lives for Sr-90 and Cs-137, the main sources of radioactivity in fallout. 115 half-lives results in a dilution of 4.1538x10^34 to one — beyond homeopathic
delusions dilutions. And that's even before dilution by wind scattering.
One common claim is that the sand around the city had vitrified similar to the trinity site in New Mexico. However, what was actually found was the dumping ground for broken pots that were often made by vitrifying sand in a kiln.
 What really happened
Though the Indus Valley Civilization may not have been a nuclear armed state, it is arguable that, in other ways, they were the most advanced civilization of their day by far. For example, we don't really have any evidence the Indus built Pyramids or Ziggurats like the contemporary Egyptians or Mesopotamians, for example, but rather built and invented things like covered sewers and flush toilets, hierarchical grid planned cities with paved roads, effectively universal access to water , an octal-decimal metric system  and even the assembly line . 
Though the Indus People had arms , they were most likely for defense against raiders, and no conclusive evidence of military aggression has been shown for the Indus Valley Civilization, thus achieving one of longest periods of peace in the history of human civilization.
Though the Indus Script is still undeciphered, its ubiquity in both place (a text has been found as far away as Somalia!) and usage points to that a level of literacy among the Indus far higher than in all other societies existing in the Third Millennium BCE bar none .
The ancient cities weren't built near any source of water like river or lake . The Indus River near which Mohenjo-daro was built, gradually changed its path so the residents were left with no source of water. Hence, they gave up the city and moved to some other place near to water. Its been speculated that the residents of Mohenjo-daro, after leaving the city got settled in the banks of river Ganges.
- ↑ *Best evidence of atomic bomb in ancient civilization essay
- ↑ *Excavations at Mohenjo Daro
- ↑ *Themes in Indian History, page 18
- ↑ The Mythical Massacre at Mohenjo-Daro
- ↑ Evidence at Mohenjo-Daro
- ↑ http://www.mohenjodaro.net/ancientdrains83.html
- ↑ http://www.cpreec.org/pubbook-traditional.htm
- ↑ http://www.tifr.res.in/~archaeo/papers/Harappan%20Civilisation/Harappan%20Weights.pdf
- ↑ McIntosh, Jane.(2008) The Ancient Indus Valley: New Perspectives. ABC-CLIO.
- ↑ http://www.cic.ames.cam.ac.uk/pages/mcintosh.html
- ↑ http://www.ancientindia.co.uk/indus/explore/nhr_spearhead.html
- ↑ http://www.amazon.com/Ancient-Cities-Indus-Valley-Civilization/dp/0195779401