The president's Marine One helicopter landed in the private Walled Garden at the Windsor estate

Prince William and his wife Catherine were on hand to meet the president and first lady Melania Trump, walking them over to be greeted by the king and Queen Camilla

Carriages have been polished, hundreds of troops have been drilled to perfection, the family silver is being laid out, and diamonds are being dusted off for a day of royal pageantry on the president's unprecedented second state visit to Britain

It's a spectacle with a purpose: to bolster ties with a world leader known for a love of bling at a time when his America First policies are putting pressure on trade and security arrangements globally

Trump arrived in London late Tuesday and said he loved being back in the United Kingdom, calling it a "very special place." Asked if he had a message for Charles, he said the king was a longtime friend of his and well-respected

The backdrop for day one is Windsor Castle, an almost 1,000-year-old royal residence with gilded interiors, crenellated towers and priceless artworks. A gigantic royal standard, the flag used for official celebration days, flew from the castle's Royal Tower as the king and queen prepared for the Trumps to arrive by helicopter from London, where they spent Tuesday night at the US ambassador's residence

The prospect of a visit to the castle has seemed to enchant Trump, who ditched his trademark bluster and described the invitation as "a great, great honour"

"I think that also is why he seems so visibly excited about the second meeting, because it isn't an invitation given to (just) anyone," said George Gross, an expert on the British monarchy at King's College London

After a day of royal pomp, Trump will hold talks Thursday with Prime Minister Keir Starmer, who will tout a new UK-US technology deal. The British government hopes the deal, and billions in investment from US tech firms, will help show that the trans-Atlantic bond remains strong despite differences over Ukraine, the Middle East and the future of NATO