Museums
There are over 200 museums in London. Here's my pick. If you want to see a list of all look here.
I've written down each museum's website, the nearest Underground station and a reference on a Google map to make it easy to find. There is also a price for paid museums, but it is approximate so that you know how to consider it. The price may have gone up in the meantime, but discounts may also apply to children, families, students and seniors (most of the time, feel free to ask).
National free museums
National museums are free in London (donations may be collected and special exhibitions may be chargeable).
British museum https://www.britishmuseum.org/
Tottenham Court | Holborn
The museum is huge. If you watch every exp for 15 seconds, it would take you a few years without days off to watch everything. Special emphasis is placed on the historical findings of ancient Egypt, Greece and Rome. There is no hope of seeing everything, but the overall impression is powerful.
Natural History Museum https://www.nhm.ac.uk/
South Kensington
Everything possible related to nature. From dinosaur skeletons to butterflies.
National Gallery https://www.nationalgallery.org.uk/
Charing Cross
Over 2,000 paintings from the Middle Ages to the present day. Da Vinci, Botticelli, Caravaggio and Van Gogh.
Science Museum https://www.sciencemuseum.org.uk/
South Kensington
Everything related to science. Reconstruction of the first (mechanical) computer, Apollo lunar landing capsule, Watt's steam engine. Lots of interesting things for children too. My favourite.
Victoria and Albert Museum (V&A) https://www.vam.ac.uk/
South Kensington
Over 2.5 million artworks and design objects. One of the largest collections in the world. Fashion, furniture, sculptures, jewellery and more.
Tate Modern https://www.tate.org.uk/visit/tate-modern
Southwark | St Paul's
Modern art. It is located in a converted building of an old power station. Suitable for a visit together with a visit to St Paul's Cathedral, as they are connected by a pedestrian bridge - the Millennium Bridge.
Museum of London https://www.museumoflondon.org.uk/museum-london
St Paul's | Barbican
Everything about London from ancient times to the present day. Interesting stuff, but with an ugly messy structure. You want to go see something according to the sign, but it leads to a dead end corridor or back to where you came from.
Imperial War Museum https://www.iwm.org.uk/visits/iwm-london
Lambeth North | Elephant & Castle
Facts about wars from WWI to the present day.
National Maritime Museum https://www.rmg.co.uk/national-maritime-museum
Cutty Sark for Maritime Greenwich
Maritime history. Old maps and ship models. Admiral Nelson's uniform as he wore it at the Battle of Trafalgar.
V&A Museum of Childhood https://www.vam.ac.uk/moc/
Bethnal Green
Toys, dolls, board games - everything related to childhood from 1600 to the present. There are also indoor attractions that children can participate in.
Sir John Soane’s Museum https://www.soane.org/
Holborn
Home of a famous architect. Lots of paintings and antiques.
Guildhall Art Gallery and Roman Amphitheatre
Bank | St Paul's
Contains an old amphitheatre found during excavations when the gallery was built.
Wallace Collection https://www.wallacecollection.org/
Bond Street
18th century French art. Titian, Canaletto and Rembrandt. The building itself is also worth seeing.
National Portrait Gallery https://www.npg.org.uk/
Charing Cross | Leicester Square
The largest collection of portraits in the world.
Tate Britain https://www.tate.org.uk/visit/tate-britain
Pimlico
British Art since 1500.
Geffrye Museum https://www.museumofthehome.org.uk/
Old Street
Changing British homes through the ages. Each room is decorated in the style of a different era.
Wellcome Collection https://wellcomecollection.org/
Warren street
Science, medicine, psychology. Darwin's walking stick can also be seen. :-)
Museum of London Docklands https://www.museumoflondon.org.uk/museum-london-docklands
Canary Wharf
The history of London as a port city.
Other museums
Clink Museum https://www.clink.co.uk/
>=£7.50 London Bridge
The old prison. Quite a terrifying place where you can get a picture of yourself behind bars as a souvenir.
London Transport Museum https://www.ltmuseum.co.uk/
>=£17.50 Covent Garden
Vehicles, photos, posters, sound recordings, maps, uniforms, badges, films and videos. Everything related to transport in London.
Design Museum https://designmuseum.org/
>=£23 High Street Kensington
Any design from cars to three-legged stools.
Royal Air Force Museum https://www.rafmuseum.org.uk/london/
free Burnt Oak (far)
All about the British Air Force.
Churchill War Rooms https://www.iwm.org.uk/visits/churchill-war-rooms
>=£19 Westminster | St John's Park
Underground spaces from where the country was run during the war.
Madame Tussauds https://www.madametussauds.com/london/
>=£29 Baker Street
World famous wax museum. Several statues are made from "originals" because Madame got her hands on the severed heads of many celebrities.
HMS Belfast https://www.iwm.org.uk/visits/hms-belfast
>=£16; London Bridge
Battleship, anchored forever.
Charles Dickens Museum https://dickensmuseum.com/
>=£9 Russel Square | King's Cross St Pancras | Chancery Lane
Over 10,000 items related to the famous writer.
The Queen's House https://www.rmg.co.uk/queens-house
>=£10 (with a guide)
The infamous Henry VIII was born in this house.
Bank of England Museum https://www.bankofengland.co.uk/museum
free Bank
History of banking and money.
Jewish Museum London https://jewishmuseum.org.uk/
>=£8.50 Mornington Crescent
History of the Jewish People. Judaism. The Holocaust. And many more...
Kensington Palace https://www.hrp.org.uk/kensington-palace/
>=£15.50 Queensway | Notting Hill Gate
You cannot see the whole palace, only a part is open to visitors.
Sherlock Holmes Museum https://www.museumoflondon.org.uk/museum-london-docklands
>=£15 Baker Street
"Museum" of a famous book character.
London Sewing Machine Museum https://www.craftysewer.com/...
Free Tooting Bec
Unfortunately, it is only open on the first Sunday of every month. :-(
Royal Academy of Music Museum https://www.ram.ac.uk/museum
free Baker Street
An incredible number of musical instruments. Also documents, pictures... Many famous Cremona string instruments and if you're lucky, you can even hear some of them.
The Postal Museum https://www.postalmuseum.org/#
>=£10 Chancery Lane | King's Cross St Pancras
Postal matters. A lot is especially designed to make it interesting for children.
The Old Operating Theatre and Herb Garret https://oldoperatingtheatre.com/
>=£6.50 London Bridge
A 19th century operating theatre located above the church. Various surgical techniques are demonstrated.
Museum of Brands, Packaging and Advertising https://museumofbrands.com/
>=£9 Latimer Road
Over 12,000 parcels, boxes, cups... from the era of Queen Victoria to the sixties of the 20th century.
Magic Circle Museum at the Centre for Magic Arts https://themagiccircle.co.uk/visiting-the-magic-circle/
only by special agreement Euston Square
Harry Houdini and others...
London Museum of Water and Steam https://waterandsteam.org.uk/
>=£12.50 South Ealing (far enough)
Steam engines and locomotives. If you want to see these in action, plan your visit for a day off or a Bank Holiday.
Anaesthesia Heritage Centre https://www.aagbi.org/education/heritage-centre
free Regents Park
More for medical enthusiasts. All about pain and painkillers.
Brunel Museum https://www.brunel-museum.org.uk/
>=£3 Canada Water
Marc Isambard Brunel and his son Isambard Kingdom Brunel were the engineers who first began to build large tunnels under the river.
London Canal Museum https://www.canalmuseum.org.uk/
>=£5 King's Cross St Pancras
London's canals, shipping and freight on these.
The Cartoon Museum https://www.cartoonmuseum.org/
>=£7 Tottenham Court Road
Animated films and comics.
The Cinema Museum https://www.cinemamuseum.org.uk/
>=£10 Elephant & Castle
Everything from the cinema. Just from the cinema, not from the films. Posters, decor, seats and even bits of carpets.
Dennis Severs' House https://dennissevershouse.co.uk/
>=£10 Liverpool Street
18th century house. Its ten rooms have an air of the past, as if the residents had just left here.
Fan Museum https://www.thefanmuseum.org.uk/
>=£4 Cutty Sark for Maritime Greenwich
Fans from the 11th century. Located in two nice 18th century houses.
Freud Museum https://www.freud.org.uk/
>=£7 Finchley Road
Sigmund Freud settled in this house in 1938, having fled from the Nazis in Vienna. The entire interior has been preserved, including the famous sofa.
Kirkaldy Testing Museum https://www.testingmuseum.org.uk
>=£5 Southwark
Museum of Engineers and Technology Enthusiasts. Among other things, a 116 ton fully operational 'test machine'.