The land now known as Turkey was of critical importance to the development of modern civilisation. This importance was at its peak when western and eastern traders, particularly from Europe and Asia Minor, had to travel through the country.
As a result, many cultures, religions, commercial and engineering skills have influenced the country's character.

In earlier eras, nearby streams and rivers were the source of water for today's capital Istanbul, then the growing city of Byzantine.
A reliable water supply was important to the community's survival, during war or siege times.
To solve this problem, people hid their water lines underground and stored water. It is said that even church basements were carefully sealed and plastered with water-resistant mortar to transform them into storage cisterns.

The Basilica Cistern's Arches and Columns

AQUEDUCTS

The arrival of the Roman Empire brought an initial period of turmoil but, paradoxically, it also established a long period of peace, as the country was protected by the might of one of the most powerful empires the time.
Hidden pipelines were no longer needed to maintain a reliable water supply and aqueducts became common. These could usually be constructed faster than tunnels, took advantage of the natural topography and ensured a constant water supply.
These pipelines were not subject to the high pressures of those which had to follow the ground line of the hills and valleys.
Most of the aqueducts along the route from the mountains to the city were open channels constructed from stone and laid along the mean hydraulic gradient.
Those close to the city were fitted with pipelines. In selected locations, this allowed engineers to build on a line other than the gradient and to turn it into a pressure system.

Many ancient civilisations used lead pipes to build pressurised systems. The biblical town of Pergamum (now Bergama), southeast of Istanbul, was one such installation. A 270mm lead pipeline in the shape of an inverted siphon carried water from a higher level, down to the floor of the valley and up to the hilltop city some 160m above its lowest point.

STONE PIPES

Byzantine had no ready supply of lead, so its pipelines were made from stone marble or clay. Those pipelines were usually hewn from stone cubes. A common size was 530 x 530 x 530mm, with a 170mm hand-cut hole in the middle (i.e. the wall thickness was about bore size).
The end faces of each pipe block were dressed smooth, with a socket at one end and a projecting lip at the other. With mortar caulking, they interlocked to form a rigid, solid watertight tube.
Stone is generally considered to have negligible tensile strength, which is why plumbers would not consider using it in this way today.

Inverted siphons were used extensively throughout ancient times to carry water down from one hill top, across the floor of an intervening valley and up the other side, particularly in those countries under Roman rule.

Ground conditions, financial constraints and available resources (were there enough slaves on hand?) determined whether aqueducts or siphons were used.

In some instances, the excessive cost of building an aqueduct could be overcome by dropping a line to run off the floor of the valley. The line would rise to a higher plateau, forming a siphon to ensure water flow to the hilltop town or city.

Intricate carving and roof brickwork

PENALTY CLAUSES

A hefty penalty clause in a construction contract is not a new idea. One ancient construction of fortified walls along the hills north of Istanbul was built in two identical sections. The walls extended to the waters of the Bosphorus, a stretch of water joining the Sea of Marmara to the Black Sea. It is still visible during a half-day cruise.