Ten members of the royal family have been visiting attractions across the UK as part of British Tourism Day.
The Queen was amused by a miniature London in Legoland
The Queen and Prince Philip inspected a miniature version of Buckingham Palace on a visit to the Legoland theme park in Windsor, Berkshire.
The Prince of Wales donned a kilt and headed to Edinburgh, where he visited a whisky heritage centre and chatted to children and visitors in the Royal Mile.
It is hoped the royal visits will help counter recent sharp falls in the number of foreign tourists to the UK, following 11 September, the war in Iraq and the Sars outbreak.
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The Duke of Edinburgh, who is celebrating his 82nd birthday, stepped on board a miniature train at Legoland to see a life-size statue of himself made out of Lego.
The Queen was amused by a mini changing of the guard outside a tiny version of her London palace.
The duke was fascinated by the detail of the models, but pointed out that a mini-milk cart was delivering to the wrong door, said managing director Mads Ryder.
The royal couple later headed to London for the official opening of the
Britain and London Visitor Centre on Regent Street.
Prince Charles surprised many visitors to the Scottish capital when he shook their hands and spoke to them while on a walkabout.
"I'm glad to see Americans are coming over here," he told one US visitor. "I had heard they were not. You are all so brave coming over."
Meanwhile, other royals have been visiting a plethora of historic sites and beauty spots.
- Prince Andrew has been in the Lake District - seeing a
Keswick theatre and a youth hostel and pub in Ambleside.
- Princess Anne has been visiting attractions in Sussex and Hampshire, including a naval museum in Gosport and Eastbourne miniature railway.
- Prince Edward dropped in at attractions around Brecon in South Wales, including a riding school, while his wife the Countess of Wessex toured Cornwall, Devon and Somerset.
- Princess Alexandra, the Queen's cousin, visited attractions in Northern Ireland - taking a ferry across Strangford Lough and visiting The Saint
Patrick Centre in Downpatrick, Co Down.
- The Duke of Gloucester was doing the rounds in Leicestershire, and the Duke of Kent headed to North
Yorkshire to see, among other attractions, Fountains Abbey.
It is the first time so many members of the Royal Family have been involved in a day to support an aspect of British life.
A Buckingham Palace spokeswoman said: "This underlines the importance of tourism to the national economy.
"The wide variety of venues being visited shows how much the UK has to offer tourists both from home and abroad."
One US visitor to London told the BBC the chance of seeing a member of the Royal Family would be an added bonus to a visit to the UK.
"But I'm not sure it would be the deciding factor," said Diane Duffy of Colombia, South Carolina.
She cited air fares and the strength of the dollar as hurdles to American visitors.
"And the prices of things are a little dear - more family pricing would be helpful."