In 1922, archaeologists made an exciting discovery, the remains of an ancient city from a previously unknown civilization. They named this city Harappa. Shortly thereafter, and with help from local guides, they found another city from the same civilization. They called this one Mohenjo-Daro. Since that time, archeologists have found over 1400 cities from this same civilization. We now call this the Indus Valley Civilization, since the cities have mostly been found in the Indus Valley. The Indus River is one of the world's longest, and winds from the mountains in northern India through India and Pakistan until it reaches the ocean.
Even with all the discoveries. we still know very little about the people who lived in the ancient Indus Valley civilization. We do know that the civilization lasted about 1000 years from about 2500 BCE until about 1500 BCE. We know that they built large cities with straight streets and brick houses. We have found artifacts that suggest many other activities as well. There is no question at this point that this was a very advanced civilization. How advanced is still under investigation.