I am in London right now.

[WinkyDink]

37. A spectacular place in London: The Silver Vaults, hard by Fleet St. and Dr. Samuel Johnson's

house and St. Paul's (go to the crypt for Wren's tomb).

https://www.tripadvisor.com/Attraction_Review-g186338-d2356480-Reviews-The_London_Silver_Vaults-London_England.html

Holds not only incredible pieces of silversmith craft, but a Magna Carta, a letter from Queen Elizabeth I to Essex, a letter from George III to "my great friend" George Washington, etc.!!

Don't miss the Tower and Crown jewels!
Shop at Harrod's and on Diana's favorite street nearby, Beauchamp Place (and see the Mews area)!
Visit the fancy shops off Piccadilly on Regent St!
Take a "Jack the Ripper" night tour (meet at the Tower Tube)!
Cross over to Southwark!
Have a drink at The George!
Do not miss the TWO Guard changings: FIRST the Queen's Horse Life Guards, in Whitehall** at the far end of St. James's Park (these horses are spectacular!); then hustle afterwards through the Park to Buckingham Palace to see the "regular" Changing of the Guard!
Walk up to Covent Garden for lunch after visiting Piccadilly Circus!

And you must, above all, see everything inside Westminster Abbey. From Poets' Corner (Chaucer's tomb, as well as Dickens, etc. Not Shakespeare.) to the ornate Henry VII Chapel to the marble tombs of EI and Mary, queen of Scots, to the Stone of Scone---all simply amazing. To me, this is the pinnacle of Western Civilization.

http://www.westminster-abbey.org/visit-us

** Take a tour underneath to visit Churchill's war-time bunker and command center.

Must day-trips: Windsor (town, castle, AND Eton School); Hampton Court.

If time: Bath-Stonehenge-Salisbury. Oxford-Warwick Castle-Stratford (awesome extra = Blenheim Palace tour, Churchill's family home). Canterbury-Cambridge.