Linked as never before, China and the United States face a new challenge tackling the global financial crisis, 30 years after they formally established diplomatic ties.
Here are some milestones in the two countries' relationship:
April 1971 - "Ping Pong diplomacy" kicks off when a US table tennis team travels to China, thawing ties that had been frozen since People's Republic of China was founded in 1949.
Feb 1972 - US President Richard Nixon travels to China and meets Chairman Mao Zedong. The two countries issue the Shanghai Communique, laying out the "one-China" policy. The communique puts an end to more than 20 years of mutual estrangement between China and the US.
Jan 1, 1979 - Beijing and Washington establish diplomatic relations, and the United States ends 30 years of recognition of Chiang Kai-shek's government in Taipei. Chinese leader Deng Xiaoping visits US later in the month.
Oct 1997 - Jiang Zemin becomes first Chinese President to visit United States in 12 years.
June 1998 - US President Bill Clinton visits China.
Nov 1999 - US and China agree on terms for China's entry into the World Trade Organisation -- a move finalised in 2001.
Oct 2001 - Chinese President Jiang Zemin meets US President George W. Bush at the Shanghai APEC summit and offers to help in the US-led "war on terror".
May 2002 - Bush welcomes Hu Jintao, who was China's vice-president at that time, to the White House for talks.
Aug 2003 - Beijing hosts the first round of six-party talks, a multilateral negotiation over the nuclear issue on the Korean Peninsula. The talks mark a new diplomatic role for China and the US.
Nov 2005 - Bush visits Beijing.
Sep 2008 - China surpasses Japan as the largest holder of US treasuries.
Dec 2008 - China urges the US to do all it can to tame its financial crisis and avert global recession. The two countries pledge to continue high-level cooperation when President-elect Barack Obama takes office in January.