The discovery of the ancient ruins of Harappa by Dayaram Sahni in 1921 and of Mohenjodaro by Rakhaldas Banerji in 1922- 1923 both officers of the Archaeological Survey of India, exploded an old age myth.

It was earlier believed that the history of India began with the coming of the Aryans.

The excavation of the ruins of the highly planned cities of Harappa and Mohenjodaro pushed back the history of India by almost 2,000 years.

It proved beyond a doubt that a highly advanced urban civilization flourished in India about 4,500 years ago.

This civilization belonged to the Bronze Age and no traces of iron have been found.

This civilization is estimated to have flourished between 2500 BCE to 1500 BCE. The discovery of Indus Valley seals and pottery among the ruins of ancient Sumerian cities shows that India had trade links with Mesopotamia which was a contemporary civilization of the Indus Valley Civilization.

Mohenjodaro means 'mound of the dead' . It is located on the banks of the river Indus in the Larkana district of Sind( now in Pakistan).

Harappa is situated on the banks of the river Ravi in Montgomery district of western Punjab ( now in Pakistan).

Around 2,800 sites have been discovered so far, making the Indus Valley Civilization the largest civilization of the ancient world.

Some major sites of this civilization are Lothal and Surkotada (Gujarat), Ropar (Punjab), Kalibangan (Rajasthan), Alamgirpur (Uttar Pradesh) Banawali(Haryana), Rakhigarhi (Haryana) and Dholavira(Gujarat)

The excavations carried out at various sites proved that around 4,500 years ago, highly civilized people lived in this region.

It gave the world its earliest cities, its first town planning, its first architecture in stone and clay and its first example of sanitary engineering and a drainage system.

The Indus Valley cities were very well planned and followed a grid system. The main streets ran parallel to each other and cut at right angles by smaller streets dividing the city into rectangular blocks or grids.

The main roads were straight and very wide(about 30 feet) and curved at the corners to allow carts to pass easily. The streets were often paved with baked bricks.

There were two types of buildings-

1. Dwelling houses 2. Public buildings

Large blocks of houses were built along the sides of the streets. Many of the houses were double - storeyed and had flat roofs. They were of different sizes. Some were like palaces while others had only two rooms. They were made of very good quality bricks. An average house had a courtyard surrounded by rooms, a bathroom, a kitchen and a well. A narrow staircase led to the rooms upstairs. These are called Dwelling houses.

The Great Granary at Harappa was a large building. Historians believed that it was used to store surplus food grains. There were two rows of granaries. Each row had six granaries. A similar Granary has been found in Mohenjodaro. All the granaries were built close to the river bank so that grains could be easily transportation with the help of boats. Some other important and striking buildings were the Great Bath and the Assembly hall. The great bath reassembled a large swimming pool while the assembly hall reassembled a palace,a prayer hall or an assembly hall. These were called public buildings.

The cities of the Indus Valley Civilization had an excellent, well-planned drainage system. The kitchens and the bathrooms( with sloping floors) had drains connected to the street drains. The street drains ran along the sides of the streets and were usually covered.They had manholes at regular intervals ( for inspection and cleaning ).

The Harappan society consisted of several social groups-- rulers, merchants, traders and artisans, farmers and manual labourers.

Wheat was the staple food. Farmers also grew barley, mustard, fruits and vegetables. Milk, meat, fish and eggs formed a part of their diet.

People wore cotton and woollen garments. Two- piece dresses were worn by both men and women. The men wore a garment similar to the dhoti while the women wore skirts. The upper garment was a shawl worn around the shoulder. Both men and women wore ornaments. They wore a headdress, earrings and finger rings. Women wore bangles, girdles, bracelets etc. The men kept beards. The women used harpins to keep their hair in place. They also used cosmetics.

The people loved to play indoor and outdoor games. They spent their free time dancing, singing and playing board games with dice. They also played a game similar to modern chess. The children played with various toys like wheeled carts, dolls, animals with movable heads, sliding monkeys, rattles and whistles. These toys were made of terracotta.

The main occupation of the Harappan was farming. Farmers grew barley, wheat, fruits and vegetables. The land was fertile and the farmers grew enough surplus food to feed the people in towns and cities.

Animals like goats, sheep, buffaloes, elephants and humped bulls were domesticated. Dogs and cats were kept as pets.

The Harappan people made pottery of various shapes and sizes on the Potter's wheel. These pots were generally glazed and painted. They made terracotta female figurines which were probably symbolic of Mother Goddess. They also knew the art of using metals.

The Indus Valley people carried on flourishing trade both within and outside India. They traded with countries like Mesopotamia (Iraq), Persia (Iran) and Afghanistan. A variety of weights and measures were used and trade was probably carried out by the barter system. A dockyard has been discovered at Lothal.

Excavated artefacts help us to form an idea of the religion of the Harappan. These include smoke-stained figures of a female deity and a three- faced figure seated in a yogic posture and surrounded by various animals, engraved on some seals.

Natural calamities, invasions by foreign tribes or a change in the course of the river Indus are some of the various theories that explain the collapse of the Indus Valley Civilization.