Trump's state visit is for the United Kingdom an opportunity to strengthen ties with the American president.
The meeting with King Charles takes place in nearly 1,000-year-old Windsor Castle with gilded interiors, towers and invaluable works of art. Trump has described the invitation to Windsor as a "great, great honor".
Trump said on Tuesday, after arriving in London, that he loves being back in the United Kingdom, which he calls a "very special place".
No American president, or any other world leader, has previously had the honor of making a second state visit to the United Kingdom.
