A man with a child stands on the Eiserner Steg footbridge amid snow in Frankfurt, Germany, on Dec. 16, 2018. A snowfall hit Frankfurt on Sunday. (Xinhua/Lu Yang)

People play soccer at the snow-covered Grueneburg Park in Frankfurt, Germany, on Dec. 16, 2018. A snowfall hit Frankfurt on Sunday. (Xinhua/Lu Yang)

People take selfies at the snow-covered Grueneburg Park in Frankfurt, Germany, on Dec. 16, 2018. A snowfall hit Frankfurt on Sunday. (Xinhua/Lu Yang)

A man runs at the snow-covered Grueneburg Park in Frankfurt, Germany, on Dec. 16, 2018. A snowfall hit Frankfurt on Sunday. (Xinhua/Lu Yang)

People paddle along the Main River in Frankfurt, Germany, on Dec. 16, 2018. A snowfall hit Frankfurt on Sunday. (Xinhua/Lu Yang)

Children sled at the snow-covered Grueneburg Park in Frankfurt, Germany, on Dec. 16, 2018. A snowfall hit Frankfurt on Sunday. (Xinhua/Lu Yang)

A woman walks past the snow-covered Goethe Plaza in Frankfurt, Germany, on Dec. 16, 2018. A snowfall hit Frankfurt on Sunday. (Xinhua/Lu Yang)