Lost London

From Wikipedia:

• Following a victory at the Battle of Hastings, William the Conqueror, the then Duke of Normandy, was crowned King of England in the newly finished Westminster Abbey on Christmas Day 1066.
• On 12 October 1934, in anticipation of his forthcoming marriage to Princess Marina of Greece and Denmark, his third cousin, he was created Duke of Kent, Earl of St Andrews and Baron Downpatrick. The couple married on 29 November 1934 at Westminster Abbey. The bride was a daughter of Prince Nicholas of Greece and Denmark and a great-niece of Queen Alexandra. It was the last marriage between a son of a British Sovereign and a member of a foreign Royal House to date.
• At the Palace of Westminster, at the time of its completion, the Victoria Tower was the tallest and largest square tower in the world.
  

Inigo Jones, born in London of Welsh parents, was a famous architect who brought Italianate Renaissance design to England.
From Wiki:

Jones' best known buildings are the Queen's House at Greenwich, London (started in 1616, his earliest surviving work) and the Banqueting House at Whitehall (1619) – part of a major modernisation by him of the Palace of Whitehall – which also has a ceiling painted by Peter Paul Rubens.

Christ Church at Greyfriars was destroyed in the Second World War; the ruins are now a public garden. However, in an ingenious use of space and to maintain architectural relevance, the main bell tower has been converted into a remarkable residence by BoyarskyMurphy.