A five-year project to restore the walls of Jerusalem’s Old City has been completed, the Israel Antiquities Authority said Tuesday.

The $4.4 million project saw workers clean and repair Jerusalem’s most significant architectural feature — the 2.5 miles (4 kilometers) of walls and seven gates constructed by the Ottoman Sultan Suleiman the Magnificent.

Suleiman’s work, seemingly driven by fears of another Christian Crusade to reconquer Jerusalem, was completed in 1541. The walls remain intact nearly five centuries later, a testament to Ottoman construction prowess and to centuries of Muslim rule in the city.

The new restoration was the first since one conducted by the British nearly a century ago.

On Tuesday the IAA announced that the project was over with the completion of work on Lions Gate, famous as the entry point for the Israeli paratroopers who took the Old City in 1967.

Eran Hemo, restoration project director at the IAA, said the work was badly needed. “We saw that physically if we didn’t do it now we’d eventually have nothing left to restore,” he said.

In 2006, several stones fell from the wall into the yard of a Catholic school in the Old City. The restoration project was approved by the government and work began the following year.

The work required decisions about which of the walls’ idiosyncrasies would be preserved and which would be removed.

Dozens of nests built by falcons and common swifts were left in place. Almond trees growing in the walls were removed, however, because their roots damage the stones.

Bullets that hit the wall near Zion Gate during fighting in 1948 were preserved. One cinderblock position built by Jordanian troops before 1967 was dismantled and then restored to serve as a reminder of the divided Jerusalem that was reunified in that year’s Six Day War.

At Damascus Gate on the city’s northern side, workers recreated stone spikes pointing skyward above the gate which had been blown apart by bullets in 1967.

The workers also scanned the walls with 3D laser equipment, allowing them to map minute details and detect potentially hazardous bulges.

Damascus Gate, on the Old City's northern side, before the recent restoration...

Damascus Gate, on the Old City’s northern side, before the recent restoration…

...and after. (photo credit: Courtesy of the Israel Antiquities Authority)

…and after. (photo credit: Courtesy of the Israel Antiquities Authority)