People take selfies in front of a giant Christmas tree displayed to celebrate the upcoming holiday season at a shopping mall in Istanbul, Turkey, Dec. 15, 2019. (Xinhua/Xu Suhui)

People pass by a giant Christmas tree displayed to celebrate the upcoming holiday season at a shopping mall in Istanbul, Turkey, Dec. 15, 2019. (Xinhua/Xu Suhui)

People pass by a Christmas tree displayed to celebrate the upcoming holiday season outside of a shopping mall in Istanbul, Turkey, Dec. 15, 2019. (Xinhua/Xu Suhui)

People pass by a Christmas tree displayed to celebrate the upcoming holiday season outside of a shopping mall in Istanbul, Turkey, Dec. 15, 2019. (Xinhua/Xu Suhui)

People pass by a Christmas tree displayed to celebrate the upcoming holiday season at a shopping mall in Istanbul, Turkey, Dec. 15, 2019. (Xinhua/Xu Suhui)