The most famous Stone Castle is the White Tower of London (Tower of London)
There are many famous buildings. Perhaps most famous are Buckingham Palace and the Tower of London.
Dick Whittington.
the world's most famous Christmas tree is situated in london at Trafalgar Square.
London
London
There are a number of well known auction houses in London; the two most famous are Christie's and Sotheby's.
That is a bit subjective. However, I would say the "London Eye" is the most famous. Located in London, England of course.
Twickenham.
Ritz London
The tower of London
London