The ancient world consisted of four great civilizations: China, Egypt, Mesopotamia, and the Indus Valley Civilization. China, Mesopotamia, and Egypt have been widely researched and are well-known to us all. But the fourth and equally important one, the far more sophisticated Indus Valley Civilization—also known as the Harrapan Civilization—seems to have been lost to the world. Only rediscovered in the twentieth century, the fact that the peaceful culture seemingly did not engage in warfare and left few clues as to its ultimate demise continues to mystify archaeologists and historians to this day.
So let’s dig right into 10 incredible facts about the Indus Valley Civilization.
Related: 10 Civilizations That Mysteriously Vanished
10 Size and Population
The Indus Valley Civilization spanned approximately 486,489 square miles (1,260,000 square kilometers) throughout modern India, Afghanistan, and Pakistan. While over 1,056 Indus Valley Civilization urban centers and villages have been identified, only 96 of these have been excavated. Many of the towns were primarily distributed within the broad area of the Indus and Ghaggar-Hakra Rivers and their smaller streams. The biggest cities, home to more than five million people, were Rakhigarhi, Harappa, Ganweriwala, Dholavira, and Mohenjo-daro.
The earliest settlement in the Indus Valley, Mehrgarh, was established around 7000 BC. Most of the Indus Valley’s inhabitants were artisans and traders who predominantly lived in villages. As these villages were constructed from easily destructible materials, including mud and wood, their everyday way of life and culture were lost with little or no trace over the ages.
From archeological digs, we have, however, come to realize that the Indus Valley Civilization was an extremely sophisticated culture with a well-organized way of doing things. Though heavily populated, its cities were not messy or disorganized, unlike most of its contemporaries in Mesopotamia and Egypt. In some instances, they would have put modern city planners to shame.
9 Urban Planning
The Indus Valley Civilization showcases the world’s first-ever designed cities, organized in grid patterns, with streets traversing at right angles. These advancements in city planning were older than that of the Hippodamus of the Miletus era, who many consider to be the “father of European urban planning.” The main streets of every city were built in a North-South line while secondary roads were laid out in an East-West line. Besides being really well-designed, these cities had excellent drainage systems, and all followed a similar pattern and layout. Even the bricks of the houses had the exact same dimensions.
The main roads were often up to 33 feet (10 meters) wide, leading archaeologists to believe that marketing activities took place. In Harappa, the streets were even paved with baked clay bricks to promote ease of movement for their ox-wagons and featured channels running alongside them to remove excess surface water.
In fact, their wastewater system was so innovative that they had completely separate channels lining the streets for wastewater and rainwater. The wastewater channels and drains were placed underneath the ground and could be opened through terracotta lids when they needed cleaning. Even the impressive aqueducts built by the Romans only followed thousands of years later!
8 Hygiene and Sanitation
It has been discovered that the ancient inhabitants of the Indus Valley Civilization placed a high priority on hygiene and sanitation and led relatively healthy, safe, and clean lives. A vast amount of public baths, a unique water conservation system, a water supply throughout every house, tidy sewage systems, and impressive underground wastewater systems all highlight the role of hygienic practices in the lives of its citizens.
The waste bins installed everywhere along the streets of Mohenjo-daro are even more noteworthy. It demonstrates that even when looking at all other earlier civilizations, the society of the Indus Valley was far ahead of the times when it came to civic aspects. These waste bins were essentially brick containers and were used mainly for getting rid of any unwanted items and for garbage disposal by the citizens.
All the metropolitan areas excavated throughout the Indus Valley have been intricate and organized with significant architectural design and highly developed Bronze Age techniques. However, despite these defining characteristics of social intricacy, nobody has ever uncovered evidence of the usual elaborate crypts, personal shrines, sizeable temples, or typical royal residences that we’ve come to expect from these ancient civilizations. According to historians, this might mean that the Indus Valley Civilization was an equitable or democratic society.
We have had almost a century of excavations and research, and definitive proof for a dominant elite or even a class of managerial hierarchy has yet to emerge. The reason this can’t be found isn’t due to the Indus society’s lack of complexity and sophistication but rather due to common misunderstandings and flawed assumptions about the wealth distribution, personal relationships, expertise, and urbanization of humanity’s ancient past. The civilization of the Indus Valley merely confirms that any form of a managerial or power elite is not necessary for social sophistication and complexity.
The economy of the Indus Valley was focused on agriculture, trade, and commerce. During the Middle Bronze Age, Mesopotamian (Sumerian) scribes frequently made references to a flourishing trade with “Meluhha.” Meluhha was a prolific trading nation with strong economic ties to the Sumerians and transported large quantities of wooden products and ebony. Sesame oil and other extremely valuable or luxurious items, such as lapis lazuli, were mostly shipped from Meluhha, which archeologists believe was the Indus Valley Civilization.
Apart from their thriving import and export trade, as demonstrated by the discovery of the massive Lothal Dockyard, the Indus Valley Civilization was the world’s first cotton producer, with the earliest evidence and use of cotton discovered in Mehrgarh dating back to the 6th century BC. Farmers in the valley were also the very first to refine spinning and weaving techniques, and fair trade was ensured by a system of weights and measures made from limestone, some of which have been uncovered in and around the Lothal Dockyard.
5 Artists and Creativity
During the Indus Valley era, artists and their wares were quite sophisticated. Their artifacts demonstrate a high level of accomplishment in terms of their aesthetic value and the wide variety of materials used, including earthenware, copper, bronze, and other native rocks. They also perfected the early art of bead-making. There has been a notable rise in artistic endeavors from the 3rd millennium BC. Recoveries from the various archaeological sites have included numerous statues and sculptures, pottery, jewelry, clay figurines, and so forth.
A fascinating discovery was the bronze sculpture of the “Dancing Girl,” demonstrating the expert knowledge the Indus people had in metal twisting and casting. It also points to the significance of dance as an art or entertainment form in their ancient society.
Famous archaeologist Sir John Marshall said, “When I first saw her, I found it hard to believe that she was prehistoric.” The Dancing Girl, as well as other marvelous works of art, were created using a now-lost wax casting technique, recorded millennia before the art forms of the Greeks.
4 Advances in Architecture
Harappa used to have very advanced granaries. In fact, the technology used to build them could only be found again in Rome more than 2,800 years later. Built on raised platforms to ensure their safety during floods, the six granaries uncovered at Harappa were approximately 148 feet (45 meters) long and 49 feet (15 meters) wide.
The inhabitants of this ancient civilization also used two kinds of basic burnt bricks in everything. One measured precisely 2.75 x 5.5 x 11 inches (7 x 14 x 28 centimeters), while the other measured exactly 3.9 x 7.9 x 15.7 inches (10 x 20 x 40 centimeters).
The larger bricks were used to construct large public buildings, whereas the smaller bricks were used to build the inhabitants’ houses. Whether the bricks were large or small, they were made to exact dimensions in all the cities and followed a ratio of 1:2:4. With this architectural feat, they were able to build numerous dams and water reservoirs. These dams and reservoirs served a dual purpose. They protected the cities from floods but also provided water to the cities throughout the year, including the dry seasons. 
3 Houses of the Indus Valley Civilization
The architectural design and masonry of the Indus people were so developed that residents in the city of Harappa had two and three-story residences. These comfortable family homes also had spacious courtyards and easy-to-access flat terraces. Hardly any of the Indus Valley households seemed to have windows looking toward their streets and would usually have only one entrance. Instead of looking towards the streets, the windows and doors of the houses would face inward, toward the courtyard; as such, they were actually intelligently designed and built to minimize noise and dust pollution inside the house.
These houses of Harappa were so wonderfully modern that many believe they were also the first in the world to have their bathrooms affixed to their homes. Almost all of the excavated residences have shown evidence of bathrooms, restrooms, toilets, and sewage systems. As previously mentioned, every home also had access to running water throughout the year.
2 Advancements in Metallurgy
The Indus Valley Civilization had an in-depth understanding of metallurgy. Their metal products were exported far and wide and were created using various metal products, including lead, copper, bronze, and alloys. They also showed remarkable skill and had a variety of techniques for smelting copper with a wide range of other metals.
Golden necklaces tinier than 0.25 mm in width have been excavated at the Lothal archeological site. Other precious metal artifacts have also been uncovered in Rangpur, Mohenjo-Daro, and Harappa. Copper implements were produced using some sort of casting method, while bronze items were made from single hammered sheets.
Their knowledge was, in fact, so advanced that they already evaluated the pureness of gold utilizing the touchstone technique, a technique that is used in various parts of the world to this day.
1 The Indus Valley Script Has Never Been Deciphered
One of the main reasons we don’t know more about the Indus Valley Civilization is that their script has never been deciphered. Thousands of Indus texts have been discovered, mainly from Harappa and Mohenjo-daro, but also in the faraway places of their trading partners all along the Persian Gulf and Mesopotamia. Most of them are inscribed on humble stone seals, around one square inch (2.5 square centimeters), just above images of animals, such as an elephant, bull, or even a unicorn-type creature. In smaller amounts, inscriptions have also been found on clay tablets, metal objects, and pottery.
There has been a permanent $10,000 prize for anybody who uncovers an Indus text of more than 50 characters since 2004, which will remain valid throughout the entire life of the historian Steve Farmer, a staunch critic of the opinion that the Indus Valley Civilization was literate.
Currently, many scholars are arguing for a prehistoric form of Dravidian, a group of languages that are today mostly found in small pockets around India and Pakistan—relatively close to the heart of the ancient civilization. Likewise, a few others favor an Indo-European language linked to prehistoric Sanskrit, which encourages Hindu nationalist arguments about the ancient culture. However, until it’s fully deciphered, we may never be 100% sure.