Hatra flourished as a trading centre in its time, as caravans passed through this region, on their way from Mesopotamia, Arabia and Persia in the east and the Levant, Asia Minor, Europe and North Africa in the west. Together with Palmyra (now Syria), it was one of the main stops for the caravans.
Hatra was throughout its history allied with larger powers, but represented a fairly small kingdom of its own, bordered by the two rivers of Euphrates and Tigris. Despite its small size, the region was well placed and easy to govern, obvious reasons for its prosperity.
The Hatrans were known as good soldiers, and Hatra was able to repel many attacks by the Romans. They even developed a bomb, which was hurled by a mangonel catapult, that propelled large stones together with flaming petrol and arrows at the enemy.
All functions of Hatra took place inside two near-circular walls. The outer wall was about 8 km long, 2 km in diameter, and made from clay. A deep trench, 300 to 500 metres wide, ran between the outer and the inner wall. The inner wall was made from stone with a height of 2 metres. It had as many as 163 defensive towers, the span between them being never more than 35 metres. There were 4 gates, easy to defend, which led into the inner city.
In the centre of the circle were the several temples of the city. The temple area was about 12,000 m² large. The most prominent of the temples was the Great Temple, which in its full expanse measured 440 metres from west to east, 320 metres from north to south and 30 metres in height.
Due to the many peoples passing through, setting up companies and representations in the city, Hatra allowed the coexistence of several different religions. Temples were built for the different gods, and Hatra soon developed into an important religious centre. This made Hatra famous in its time, and it was called Bet Elaha, in Aramaic, or "House of God."
Among the gods revered here, were Nergal of Mesopotamian religion, Hermes of the Greek religion, Atargatis of the Aramean religion, Al-Lat and Shamiyah of the Arabian religion. Other temples were dedicated to Shahiru, Mithra, Maran, Shiu and Saqaya. However, it could be concluded that a syncretistic religion developed in Hatra, uniting the gods revered in the city into one pantheon. The main element of Hatran religion became the eagle, and there are numerous eagle decorations around the city.
The architecture and artwork of Hatra had its origin in Arabia, Assyria, Greece and the Roman Empire, and the city represents the most complete of any Parthian city preserved, and is the only site in Iraq included in UNESCO’s World Heritage Properties.
The language of Hatra was at least in the latter half of its history, Aramaic. The Aramaic alphabet, similar to the one used in Palmyra, was used throughout the history of Hatra.
Most of the marbles statues and sculptures are now harboured in the Iraqi Museum in Baghdad and the Museum of Mosul.