The Yenikapi site is the linchpin of what the Turkish government dubs the "project of the century". The $4bn (£2.2bn) Marmaray transport project is being built by a Japanese-led consortium. There will be tunneling under the Bosphorus for the first time ever, with high-speed trains going through the deepest underwater tunnel in the world in the middle of a high-risk earthquake zone. The tunnel itself will be built to withstand quakes of 9.0 on the Richter scale in the area of the North Anatolian Fault, which runs below the Sea of Marmara nearing the walls of Istanbul. Seismologists say a large earthquake and a mini tsunami are almost inevitable within a generation at the latest.

The ambitious new transport system is to shift 75,000 passengers an hour and to put Istanbul behind only Tokyo and New York in the global league table for urban rail capacity.

There is no doubt the Marmaray is needed urgently. In a city of 12 million, which seems to grow by the week, the traffic congestion is a nightmare and the Bosphorus bridges are gridlocked semi-permanently. So the engineers, transport officials and urban planners are in a hurry to get the infrastructure built by the end of the decade.