The Nanjing Yangtze River Bridge is closed on Oct 28, 2016 for a major revonation project. [Photo/Xinhua]

Built in 1968, the bridge was hailed an engineering breakthrough and became the pride of the nation. It was the first modern bridge across the river to be wholly designed and built by Chinese talent and labor. School textbooks chronicle its construction and it appears in tourist souvenirs.

On Friday night, a major renovation project began. The work is projected to take 27 months, and cost about 1.1 billion yuan (about $160 million). Hundreds of tourists have been arriving to take photos at the bridge before it changes forever.

"Decades ago, China was technologically isolated from developed countries. The bridge was highly symbolic of our national struggle and its completion raised the national spirit," said Zhang Zhenshan, who worked on the construction 48 years ago.

"I get excited every time I cross the bridge," said Wu Zifan, 28. "It was a truly great sight, with big ships crossing under the bridge, trains rumbling by and a never-ending stream of cars. One of my fondest memories was trying to count the side lamps along the bridge, but there were so many and it was easy to lose count."

Years of heavy traffic have taken their toll on the bridge, said Chun Qing of the Southeast University and one of the leaders of the renovation project.

The bridge will be strengthened structurally. There are large cracks on the cement highway and along the rails. Ornamentation needs to be renovated and the drains also need to be repaired.

"We will try our best to retain the original look of the bridge," said Chun.

While the bridge is closed, commuters will have to use ferries, the second Nanjing Yangtze bridge, completed in 2001, or tunnels below the river.

"Repairing the bridge is the preservation of history. I hope that after 27 months, the bridge will be more magnificent yet," said Zhang Heng, a Nanjing resident.