King Charles III and Queen Camilla are visiting the US - the first British state visit to the country since Queen Elizabeth II's visit in 2007. The trip, which comes as the US approaches the 250th anniversary of its independence from Britain, is meant to celebrate the strong relationship between the two countries. State visits are taken when a head of state is invited for a formal stay by another country, in this case the US. As heads of government, British prime ministers conduct "official