Why Nancy Pelosi went to Taiwan and why China is angry

People walk past a billboard welcoming US House Speaker Nancy Pelosi in Taipei, Taiwan (Chiang Ying-ying/AP)

When US House Speaker Nancy Pelosi flew into Taiwan on an Air Force passenger jet, she became the highest-ranking American official in 25 years to visit the self-ruled island.

China announced military manoeuvres in retaliation, even as Taiwanese officials welcomed her and she headed to her hotel.