ZHUHAI, June 29, 2016 (Xinhua) -- The aerial photo taken on June 29, 2016 shows the construction site of the main bridge parts of the Hong Kong-Zhuhai-Macao Bridge, the world's longest cross-sea bridge, in Zhuhai, south China's Guangdong Province. Two main bridge sections of the Hong Kong-Zhuhai-Macao Bridge joined together on Wednesday. (Xinhua/Liang Xu)