This photo taken on April 28, 2024 shows the Pupin Bridge spanning the Danube River in Belgrade, Serbia. The bridge, constructed by China Road and Bridge Corporation and opened in 2014, was China's first big infrastructure investment on the European continent. (Xinhua/Li Ying)

An aerial drone photo taken on April 28, 2024 shows the Pupin Bridge spanning the Danube River in Belgrade, Serbia. The bridge, constructed by China Road and Bridge Corporation and opened in 2014, was China's first big infrastructure investment on the European continent. (Photo by Wang Wei/Xinhua)

An aerial drone photo taken on April 28, 2024 shows the Pupin Bridge spanning the Danube River in Belgrade, Serbia. The bridge, constructed by China Road and Bridge Corporation and opened in 2014, was China's first big infrastructure investment on the European continent. (Photo by Wang Wei/Xinhua)

An aerial drone photo taken on April 28, 2024 shows the Pupin Bridge spanning the Danube River in Belgrade, Serbia. The bridge, constructed by China Road and Bridge Corporation and opened in 2014, was China's first big infrastructure investment on the European continent. (Photo by Wang Wei/Xinhua)

An aerial drone photo taken on April 28, 2024 shows the Pupin Bridge spanning the Danube River in Belgrade, Serbia. The bridge, constructed by China Road and Bridge Corporation and opened in 2014, was China's first big infrastructure investment on the European continent. (Photo by Wang Wei/Xinhua)

An aerial drone photo taken on April 28, 2024 shows the Pupin Bridge spanning the Danube River in Belgrade, Serbia. The bridge, constructed by China Road and Bridge Corporation and opened in 2014, was China's first big infrastructure investment on the European continent. (Photo by Wang Wei/Xinhua)

An aerial drone photo taken on April 28, 2024 shows the Pupin Bridge spanning the Danube River in Belgrade, Serbia. The bridge, constructed by China Road and Bridge Corporation and opened in 2014, was China's first big infrastructure investment on the European continent. (Photo by Wang Wei/Xinhua)

An aerial drone photo taken on April 28, 2024 shows the Pupin Bridge spanning the Danube River in Belgrade, Serbia. The bridge, constructed by China Road and Bridge Corporation and opened in 2014, was China's first big infrastructure investment on the European continent. (Photo by Wang Wei/Xinhua)

An aerial drone photo taken on April 28, 2024 shows the Pupin Bridge spanning the Danube River in Belgrade, Serbia. The bridge, constructed by China Road and Bridge Corporation and opened in 2014, was China's first big infrastructure investment on the European continent. (Photo by Wang Wei/Xinhua)

An aerial drone photo taken on April 28, 2024 shows the Pupin Bridge spanning the Danube River in Belgrade, Serbia. The bridge, constructed by China Road and Bridge Corporation and opened in 2014, was China's first big infrastructure investment on the European continent. (Photo by Wang Wei/Xinhua)