US Speaker Nancy Pelosi’s unannounced trip to Taiwan, during her tour of Asia, has made China upset.

Ahead of her visit, China said that the US will “pay the price” if Pelosi visited Taiwan. “The US side will bear the responsibility and pay the price for undermining China’s sovereign security interests,” a Chines foreign ministry spokeswoman said.

Why is this visit so controversial? Could this visit put the US and China on a collision course? Listen in.