The correct answer to this open question is the following.
When UNESCO names a place as a UNESCO World Heritage Site, this means that the site represents a historic significance for humanity, which value cannot be counted. This also means that UNESCO is going to support the place because that town or archeological site belongs to all humanity, not only to that nation where is located, due to its greatness, and cultural/historic importance.
In this case. Mohenjo Daro is an old archeological site located in Sindh, Pakistan, in what once was the Indus Valley Civilization. Archeologists believed that was built approximately in 2500 BCE, in a time when other ancient civilizations such as Sumeria or ancient Egypt developed.