Photo taken on May 24, 2018 shows explosions of the No. 4 tunnel at the nuclear test site of Punggye-ri, the Democratic People's Republic of Korea. The Democratic People's Republic of Korea has confirmed the demolition of its nuclear test site at Punggye-ri on Thursday, saying that all the tunnels have been collapsed by explosions and their entrances completely closed, according to the Korean Central News Agency (KCNA). (Xinhua/Cheng Dayu)