AMNA NAWAZ: In the day's other headlines: President Trump enjoyed a warm welcome to Britain's Windsor Castle today, where his royal hosts put on a display of pageantry, pomp and military parades.

It's an unprecedented second state visit for Mr.

Trump, and it comes with both regal spectacle and real-world diplomacy.

That's due to include the signing tomorrow of a civilian nuclear power deal and a massive transatlantic tech agreement.

At Windsor Castle, a chopper-sized personal welcome from the prince and princess of Wales and a gilded entrance fit for a king, a queen and an American president, as President Trump was greeted with the full royal treatment upon arrival in the United Kingdom.

That included 1,300 armed troops and a royal review of guards, all part of the largest military welcome for a state visit in British history.

King Charles later escorted President Trump into the oldest castle in the world to view the royal collection.

DONALD TRUMP, President of the United States: That is so amazing.

AMNA NAWAZ: Tables adorned with mementos of U.S.-British relations, including documents of America's independence nearly 250 years ago.

By comparison, today's pomp and circumstance was a stark upgrade from Trump's last state visit in 2019.

DICKIE ARBITER, Former Press Secretary to Queen Elizabeth: The president is a bit of a showman.

The U.K.

wanted to put on a good show, and they were able to do it with the blessing of the king.

So all the stops were pulled out, soft diplomacy from the royal family.

It seemed by all accounts and looking at all the pictures that have come out that the king and President Trump got on extremely well.

AMNA NAWAZ: Dickie Arbiter is a royal watcher and former press secretary for Queen Elizabeth II.

DICKIE ARBITER: I suppose it was done because the U.K.

wants to please Trump.

The U.K.

wants something out of America.

We have got all these tariffs going, going on.

Various countries have got 50 percent, one or two have got 100 percent, U.K.

25 percent.

They want to get it down.

Our economy is not very good at the moment.

Our government is not particularly good either.

AMNA NAWAZ: For the first time ever during a state visit, the military's beating retreat ceremony was performed, today complete with soldiers dressed as American revolutionaries and a flyover of British Red Arrow jets.

The pageantry was not without protests, including images of President Trump and the late convicted sex offender Jeffrey Epstein together projected onto the side of Windsor Castle last night.

PROTESTER: Donald Trump, you can't hide!

AMNA NAWAZ: And, today, thousands pouring into the streets of London to show their dissent, all this as the U.K.

announces tens of billions of dollars worth of technology deals with American tech giants Microsoft, Nvidia and OpenAI to open new data centers in the U.K.

Tomorrow, a new deal is expected to be unveiled for the U.S.

and U.K.

to share American nuclear reactor technology and lower nuclear regulations.

KING CHARLES III, United Kingdom: The ocean may still divide us, but in so many other ways, we are now the closest of kin.

AMNA NAWAZ: But, tonight, the festivities continue to unfold, as the special relationship between these two nations enters a new era.