Xi Jinping and Kim Jong Un attended an elaborate celebration in Pyongyang Thursday celebrating 70 years of diplomatic relations between China and North Korea, underscoring their alliance amid challenges posed by the United States. Fireworks burst into the sky over the May 1 stadium in the North Korean capital, while enormous signs proclaimed that the two countries were «true and reliable comrades.» «Long live the unbreakable friendship and union between the Democratic People's Republic of Korea (DPRK) and the Chinese people,» one banner said.