Museums/Churches I recommend in London (from the Kate thread but expanded here). All of these are free.
1. The British Museum - has some of the 'great items' of history e.g. the Rosetta Stone but one a lot of people don't know is there is the Cyrus Cylinder - often regarded by historians as the first statement of 'human rights' - although all it really does is guarantee Babylonians the right to follow their own religion but it was still radical in its day for even allowing that. The Persians, contrary to the way they are portrayed in western movies such as that travesty called '300' were a very tolerant, multicultural society. The museum also has the Oxus Treasure which is a magnificent of Persian gold working (when I say Persian I am talking about 550 - 330 BC). There is a lot more of course - Roman, Anglo-Saxon, Norman, medieval, Tudor, Stuart, Georgian, Victorian and right down to the modern day. I believe you could visit every day for a year and still find things that you haven't seen ...
2. The National Art Gallery - a full range of art works from the ancient to the present with some great medieval works as well as Turners, Constables etc.
3. The National Portrait Gallery - as it says 'portraits'. Many of the great portraits of the monarchs are here. I am down to the Stuarts having seen and spent some time looking at the great portraits of the earlier monarchs. One thing I love (and hopefully with refurbishment) is that the art works are set up chronologically.
4. The Imperial War Museum - great museum of the British military but acknowledging the contribution of the Empire and Commonwealth. It is one of the few places where I have seen one of the famous taxis that transported the French army from the German border to The Marne in 1914 (there is another in Les Invalides in Paris of course). It brought home to me just how desperate those days were for France to realise that they used such vehicles to get the army into the right place to stop the Germans in sight of Paris.
5. St Martins-in-the-Field - also in Trafalgar Square so works in well with a visit to the Portrait or National Galleries - lovely church, the parish church for the royals when in residence in BP. Queen Mary was a regular worshipper there. They usually have a lunch time communion service and evensong at night. They also have a crypt in which you can get a meal. Personally I prefer the Italian restaurant just around the corner but that is me.
6. Around St Paul's there are many churches, often open during the day with an 'honesty' box if you want to take a postcard and chance to also make a donation. Many of them were also designed by Wren after the Great Fire. One 'day' I love when I go to London is my visit to St Paul's and then a walk around the streets before heading down to the Tower and either getting the tube home, or using the river to cruise back up to Westminster (I usually stay either at Royal Horseguards, within walking distance of Westminster or near Kensington Gardens - so within walking distance). On a really pleasant day I might even cross the river and walk along the other side of the river - the Queen's Silver Jubilee Walkway is along there - to reach 'home'.
7. Another church worth visiting, but it is only open for services if my memory serves, is the Queen's Chapel at St James'. The Chaplain who takes the service will be one of The Queen's chaplains and anyone can attend. You may find a royal in attendance but if it is one of the very senior royals then you will have to have a full security check, unless you are a regular (or that is what I was told when I went there - by accident).
8. The Museum of London is exactly that - a museum that covers the history of London from pre-history to the present. It is in the heart of what was Roman London and really tells the story of the city. It is specific of course to the city.
9. If you get a chance try the Guildhall Art Gallery as underneath is the Roman amphitheatre and the way it was set up in 2002 (and I assume still is ... I haven't had a chance to get back) was so that when you entered you felt like you were there. They have used CGI to build on the surviving parts of the amphitheatre to show what it would have been like. I have an interesting visit in 2002 as I went into the art gallery as they had a display called 'The Queen and the City' which was a series of photos, paintings etc of the Queen and her visits to the City of London from George V's Jubilee to many of her own visits. To get to that exhibition I had to pass the statue of Margaret Thatcher and she looked so lifelike with even her handbag. I went past her to the exhibition and then down to the amphitheatre and by the time I came out the police were in attendance. The person who entered after me had managed to somehow smuggle in a cricket bat which, when there was no one around, they had used to remove Maggie's head. I was probably the last person, besides this person, to see that statue as it had originally been carved. https://www.theguardian.c...02/jul/04/artsnews.redbox
The perpetrator was sent to prison for 3 months.