Aphrodisias:

Tetrapylon

The Tetrapylon with Temple of Aphrodite
The Tetrapylon Before Anastylosis

The monumental gateway to the Sanctuary of Aphrodite was built in ca. A.D. 200. It led from Aphrodisias's main north-south street into a large forecourt in front of the Temple. A complete scientific reconstruction, or anastylosis, of the gateway was completed in 1991. This reconstruction was made possible by the extraordinary preservation of the structure - 85% of its original marble blocks survive. Before reconstruction, the standing ruins were dismantled, and new foundations were laid. The gateway was then painstakingly reassembled, incorporating steel reinforcing bars in the columns and other structural elements, and new cast-concrete blocks where necessary.
Panorama of Tetrapylon