Mohenjo-daro and the Indus Valley Civilisation
The Indus Valley Civilisation, also called the Harappan civilisation, flourished from approximately 3300 to 1300 BCE across a vast area encompassing modern Pakistan, north-western India, and parts of Afghanistan — covering roughly 1.25 million square kilometres, larger than either Egypt or Mesopotamia at their peaks. At its mature phase (2600–1900 BCE), it supported an estimated 5 million people in a network of over 1,000 settlements, including two major urban centres: Mohenjo-daro on the west bank of the Indus in Sindh, and Harappa on the Ravi River in Punjab.
Mohenjo-daro (Sindhi for Mound of the Dead) is the better preserved and more extensively excavated of the two principal cities. It is a UNESCO World Heritage Site and one of the most significant archaeological sites in Asia.
Urban Planning and Infrastructure
Mohenjo-daro is extraordinary for the systematic, grid-planned organisation of its streets and buildings. The city was divided into two main zones: a Citadel or high mound to the west, which contained the most architecturally significant structures, and a lower town to the east, which contained the dense residential quarters. The streets of the lower town run approximately north-south and east-west, dividing the city into rectangular insulae (city blocks) of varying sizes.
The construction material throughout the city is fired brick, standardised to consistent proportions (approximately 1:2:4 ratio of width to height to length) across the Indus civilisation's entire geographic range — a remarkable degree of standardisation that implies either central control of brick production or widely shared conventions for manufacturing. Fired brick was unusual in the ancient world: it requires substantial fuel consumption (which may have contributed to deforestation of the Indus valley's riverine forests) and implies a level of investment in permanent infrastructure that distinguishes Mohenjo-daro from most contemporary civilisations.
The Great Bath
The most famous structure at Mohenjo-daro is the Great Bath on the Citadel mound. It is a large watertight pool (11.88 metres long, 7 metres wide, 2.4 metres deep) lined with fired brick set in gypsum plaster and sealed with a natural bitumen layer to prevent seepage. Steps lead down into the pool from both ends. The pool was fed by a well in an adjacent room and drained through a corbelled drain in the corner. Surrounding the pool on three sides are porticoed galleries and small rooms, which some scholars interpret as the cells of priests or bath attendants.
The function of the Great Bath is almost certainly ritual or religious: the investment in waterproofing, the careful construction, and the architectural context all suggest a structured space for communal ablution or ritual purification, analogous to the sacred tanks attached to later Hindu temples. The bath has no precise parallel in any contemporary civilisation and points to a distinctive religious practice.
The Granary and the Citadel Complex
Directly north of the Great Bath is a large structure conventionally called the Granary, though this identification is not universally accepted. It consists of a high podium supporting a series of brick-floored compartments; wood impressions in the floor suggest it had a substantial wooden superstructure. If it was a granary, it would have served as the central storage facility for the city's agricultural surplus — a key function in the redistributive economics of early urban centres. Some scholars instead interpret it as a large residential or administrative building.
The Citadel mound contains other significant structures including what appears to be a large hall with a colonnade, and a structure interpreted as the priest-king's residence or administrative centre, though without writing that can be read, these functional identifications remain hypothetical.
The Drainage System
The drainage system at Mohenjo-daro is among the most sophisticated of the ancient world. Individual houses were connected to a covered drainage network that ran beneath the streets, channelling waste water to soak pits or to drains at the edges of the city. The system required coordinated maintenance — the drains needed regular cleaning to remain functional — and implies some form of civic authority capable of organising public works. The presence of latrines in many houses, connected to the drainage system, indicates a concern for sanitation without parallel in contemporary Mesopotamian or Egyptian cities.
The Indus Script
Over 4,000 inscribed objects — primarily small steatite seals, each typically showing an animal figure above an inscription — have been found at Indus sites. The inscriptions are brief (most have fewer than 5 signs) and in a script that has resisted all decipherment attempts. The Indus script has approximately 400–700 distinct signs, suggesting a logosyllabic system (combining logograms and syllabic signs), but no bilingual text comparable to the Rosetta Stone has been found. Without decipherment, the Indus civilisation remains historically silent: we have no royal names, no records of wars or treaties, no religious texts, no administrative archives.
The language underlying the script is unknown; some scholars propose a Dravidian connection, others argue for an early Indo-Aryan or an unknown language family. The debate remains entirely unresolved.
Trade Connections
Despite the opaque textual record, the Indus civilisation's external connections are documented archaeologically. Indus seals and weights have been found at Mesopotamian sites, confirming trade with the Persian Gulf region that is also documented in Akkadian texts referencing imports from Meluhha (generally identified with the Indus region). The goods traded included cotton textiles (the Indus was probably the earliest civilisation to produce woven cotton), ivory, lapis lazuli from Afghanistan, carnelian beads, and timber. Indus weights, standardised to a binary-decimal system (in units of 0.837 grams), are found across the trade network, suggesting a shared commercial convention.
Decline and Abandonment
Mohenjo-daro was abandoned around 1900 BCE, as was most of the Indus civilisation's urban network. The causes remain debated: river course changes that disrupted agriculture and trade; progressive desiccation of the Indus plains; the disruption of monsoon patterns documented in climate proxy records; or a combination of factors. There is no evidence for military conquest or catastrophic destruction; the decline appears to have been gradual, with populations dispersing to smaller settlements in the Ganges-Yamuna plain and the Deccan Plateau.
Visiting Mohenjo-daro
The site is in Sindh province, Pakistan, near the town of Larkana (accessible by rail and road from Karachi). The site museum contains a good collection of finds including seals, figurines, and the famous Dancing Girl bronze. The Great Bath, Granary, and lower town residential areas are all accessible on foot. The site is a UNESCO World Heritage Site but faces ongoing conservation challenges from salt crystallisation in the brick fabric; visitor numbers are limited to reduce erosion pressure.