King Charles and other British royals greeted Donald Trump on Wednesday as the US president's historic second state visit to Britain began with unprecedented pomp, intense security, technology investments and protests. Trump and his wife Melania arrived at Windsor Castle, the oldest and largest inhabited castle in the world and family home to British monarchs for almost 1,000 years. He was met by the monarch, his wife Queen Camilla, heir Prince William and his wife Kate before a carriage procession through the grounds. Ahead of a lavish banquet there will be a military flypast, part of what Britain has said would be the largest military ceremonial welcome for a state visit in living memory. Trump, an overt royal fan, has...