A warning sign of floods is seen in Frankfurt, Germany, Jan. 7, 2024. Some areas in Frankfurt were flooded due to continuous rainfall and rising water level of the Main River. (Xinhua/Zhang Fan)

Benches along the Main River are submerged in flood water in Frankfurt, Germany, Jan. 7, 2024. Some areas in Frankfurt were flooded due to continuous rainfall and rising water level of the Main River. (Xinhua/Zhang Fan)

A bench along the Main River is submerged in flood water in Frankfurt, Germany, Jan. 7, 2024. Some areas in Frankfurt were flooded due to continuous rainfall and rising water level of the Main River. (Xinhua/Zhang Fan)

The river bank of Main River is submerged in flood water in Frankfurt, Germany, Jan. 7, 2024. Some areas in Frankfurt were flooded due to continuous rainfall and rising water level of the Main River. (Xinhua/Zhang Fan)

A man rows a kayak on the flooded river bank in Frankfurt, Germany, Jan. 7, 2024. Some areas in Frankfurt were flooded due to continuous rainfall and rising water level of the Main River. (Xinhua/Zhang Fan)