President elect Donald Trump had an unprecedented phone call with Taiwan's president Tsai Ing-wen.
This was enough to cause the Chinese government to flip out and China's foreign ministry says it has lodged a complaint with the US government over this call.
Incidentally, Both sides insist that it was the other side who was responsible for the phone call.
But why is a single phone call between A US president elect and Taiwan's president is considered such a huge big deal?
The Chinese government views Taiwan as a breakaway province and has adamantly opposed the attempts of any country to carry on any official relations with it.
The split between China and Taiwan goes back to 1949, when the Republic of China (ROC) government fled the mainland to Taiwan.
After Japan was defeated in World War Two, the US and Britain agreed that Taiwan should be handed over to their ally, Chiang Kai-shek's Republic of China government, which was then in control of most of China. But in the next few years, Chiang's troops were beaten back by the Communist armies under Mao Zedong.
Chiang and the remnants of his Kuomintang (KMT) government fled to Taiwan in 1949. This group, referred to as Mainland Chinese and then making up 1.5m people, dominated Taiwan's politics for many years, even though they only account for 14% of the population.
After 1945, it held China's seat on the UN Security Council and was, for a while, recognised by many Western nations as the only Chinese government.
But in 1971, the UN switched diplomatic recognition to Beijing and the ROC government was forced out. Only a handful of countries now recognise Taiwan's government.
Having inherited an effective dictatorship, Chiang's son, Chiang Ching-kuo, began a process of democratisation, which eventually led to the 2000 election of the island's first non-KMT president, Chen Shui-bian.
Washington cut formal diplomatic ties with Taiwan in 1979, expressing its support for Beijing's "One China" concept, which states that Taiwan is part of China.
China has hundreds of missiles pointing towards Taiwan. It also passed a law in 2005 which basicly states that China will use force and will invade Taiwan if it declares independence.
Despite all of China's constant bullying and threats, Taiwan remains defiant, flaunting its democracy and free society in the face of China's dictatorial Communist one party rule.
Trump's call with President Tsai Ing-wen risks infuriating China, which wants to bring Taiwan back under mainland rule. By honoring the Taiwanese president with a formal call, Mr. Trump’s transition team implicitly suggests that it considers Taiwan an independent state.