China Light Festival held at Cologne Zoo in Germany(1/10)

A child visits China Light Festival at Cologne Zoo in Cologne, Germany, on Jan. 3, 2019. The festival is held here presenting more than 50 lights from Dec. 8, 2018 to Jan. 20, 2019. (Xinhua/Lu Yang)

A child is silhouetted against a light during China Light Festival at Cologne Zoo in Cologne, Germany, on Jan. 3, 2019. The festival is held here presenting more than 50 lights from Dec. 8, 2018 to Jan. 20, 2019. (Xinhua/Lu Yang)

Children step on illuminated installations during China Light Festival at Cologne Zoo in Cologne, Germany, on Jan. 3, 2019. The festival is held here presenting more than 50 lights from Dec. 8, 2018 to Jan. 20, 2019. (Xinhua/Lu Yang)

A woman takes photos during China Light Festival at Cologne Zoo in Cologne, Germany, on Jan. 3, 2019. The festival is held here presenting more than 50 lights from Dec. 8, 2018 to Jan. 20, 2019. (Xinhua/Lu Yang)

People visit China Light Festival at Cologne Zoo in Cologne, Germany, on Jan. 3, 2019. The festival is held here presenting more than 50 lights from Dec. 8, 2018 to Jan. 20, 2019. (Xinhua/Lu Yang)

A child visits China Light Festival at Cologne Zoo in Cologne, Germany, on Jan. 3, 2019. The festival is held here presenting more than 50 lights from Dec. 8, 2018 to Jan. 20, 2019. (Xinhua/Lu Yang)

A child visits China Light Festival at Cologne Zoo in Cologne, Germany, on Jan. 3, 2019. The festival is held here presenting more than 50 lights from Dec. 8, 2018 to Jan. 20, 2019. (Xinhua/Lu Yang)

A visitor takes photos during China Light Festival at Cologne Zoo in Cologne, Germany, on Jan. 3, 2019. The festival is held here presenting more than 50 lights from Dec. 8, 2018 to Jan. 20, 2019. (Xinhua/Lu Yang)

Illuminated swans are seen during China Light Festival at Cologne Zoo in Cologne, Germany, on Jan. 3, 2019. The festival is held here presenting more than 50 lights from Dec. 8, 2018 to Jan. 20, 2019. (Xinhua/Lu Yang)

A visitor is silhouetted against a light during China Light Festival at Cologne Zoo in Cologne, Germany, on Jan. 3, 2019. The festival is held here presenting more than 50 lights from Dec. 8, 2018 to Jan. 20, 2019. (Xinhua/Lu Yang)