Stand on the pedestrianised stones of Trafalgar Square and the city arranges itself around you: Nelson's Column and the lions above, the National Gallery behind, and the Thames a short walk away. That single square is a fair introduction to how London works, because the landmarks, museums and parks that matter most sit close together and are easy to string into a day on foot and by Tube.
This guide suits the first-time visitor with limited time, and the returning visitor who wants to concentrate on the centre rather than spread thin across the whole city. It sticks to places that are named and described in the source material, and it tells you what to combine with what, and when to go.
Note that many of London's major museums have no general admission charge, though special or temporary exhibitions usually do. Several of the sights below are outdoor and free to look at from the street, which makes them easy to slot into a walk.
Top things to do in London
1. Tower of London
London's original royal fortress by the Thames, over 900 years old, containing the Crown Jewels and guarded by Beefeaters. It is a World Heritage site, and many consider it the most haunted building in the world; guided ghost walks of the building are sometimes available, and you can have a good meal in one of the buildings on the property.
Combine it with Tower Bridge, which sits right beside it, and arrive by Tube at Tower Hill.
2. Westminster Abbey and the Palace of Westminster
The seat of the United Kingdom parliament and a World Heritage site, and the setting for royal coronations since 1066. The Elizabeth Tower is the clock tower commonly known by the name of its bell, Big Ben. The Abbey has a restaurant and a café that both serve good food.
The Palace of Westminster is open to the public only for viewing parliamentary debates, and tours of the building are available in July and August when Parliament is away on summer recess. Tube: Westminster.
3. Buckingham Palace
The London residence of the King, in Westminster. It is worth seeing even if you do not go in, and it is open for tours during the summer months only. Tube: Green Park.
The Changing of the Guard spans three locations — Buckingham Palace, St James's Palace and Wellington Barracks — and usually begins at 10:43; check the published dates before you go. St James's Park lies between the palace and Horse Guards Parade, so it makes a natural next stop.
4. St Paul's Cathedral
Sir Christopher Wren's great accomplishment in the City, built after the 1666 Great Fire of London, with its dome still seated in majesty over the City. A section of the dome has such good acoustics that it forms a "Whispering Gallery", and there is a viewing area with views of the surrounding area including the nearby Millennium Bridge.
Tube: St Paul's. The Museum of London can be reached from Barbican or St Paul's if you want to add an indoor stop.
5. Tower Bridge
The 19th-century bridge by the Tower of London near the City, decorated with high towers and featuring a drawbridge. The public are allowed access to the interior via the Tower Bridge Exhibition, with tickets purchasable online or at the bridge.
Tube: Tower Hill, which also serves the Tower of London, so the two fit into one visit.
6. Trafalgar Square
Home of Nelson's Column and the lions, and overlooked by the National Gallery. The "Fourth Plinth" has featured a succession of artworks since 1999, and the square has been pedestrianised, making it the nearest London has to a "centre".
Tube: Charing Cross, which is also the stop for the National Gallery and the National Portrait Gallery.
7. The British Museum
A treasure trove of world cultures from across the ages, on par with the Paris Louvre and New York's Metropolitan Museum. There is no general admission charge, though special or temporary exhibitions usually attract an admission charge.
Tube: Holborn. Free entry makes it easy to visit more than once rather than trying to see it all in a single pass.
8. The National Gallery
Houses the national collection of paintings in the Western European tradition from the 13th to the 19th centuries, with no general admission charge.
Tube: Charing Cross. It overlooks Trafalgar Square, so pair the two and step outside between rooms.
9. Tate Modern
One of the major galleries with no general admission charge, on the South Bank. Tube: Southwark or Blackfriars.
It sits on the same side of the river as the London Eye and The Shard, so it works well in a South Bank afternoon.
10. London Eye
The world's fourth-largest observation wheel, on the South Bank of the Thames, with magnificent views over London. Tube: Waterloo.
Pair it with a walk along the South Bank and the Tate Modern nearby.
11. The Shard
A futuristic triangular skyscraper in South Bank that dominates the London skyline and is the tallest building in the UK. There is a viewing deck on the 72nd floor open to the public, with tickets that must be booked via the website; there are also restaurants and the luxury hotel Shangri-La on the lower floors.
Tube: London Bridge. Book the viewing deck ahead rather than turning up.
12. Victoria and Albert Museum, Natural History Museum and Science Museum
Three of the major museums with no general admission charge, all clustered together. Tube: South Kensington.
Because entry is free, you can dip into more than one in a day instead of committing to a single long visit.
13. Hyde Park and Kensington Gardens
A huge open space in central London, very popular for picnics. Within Kensington Gardens, the Diana, Princess of Wales, Memorial Playground is a free playground for young children featuring a huge wood pirate ship.
Tube: High Street Kensington, Marble Arch, Green Park or Hyde Park Corner. Marble Arch also puts you at the Wallace Collection and at the monument itself.
14. Regent's Park
A wonderful open park in the northern part of central London, with London Zoo on its northern edge. Tube: Camden Town or Regent's Park.
It is a good pairing with a zoo visit, since the two share the same edge of the park.
15. St James's Park
Charming and romantic gardens ideal for picnics and for strolling around, situated between Buckingham Palace on the west and Horse Guards Parade on the east.
Walk through it before or after the Changing of the Guard, since the ceremony spans the palace, St James's Palace and Wellington Barracks.
If you only have one day
Morning. Start at Buckingham Palace for the Changing of the Guard, which usually begins at 10:43 and spans Buckingham Palace, St James's Palace and Wellington Barracks. Walk through St James's Park towards Horse Guards Parade, then continue to Trafalgar Square for Nelson's Column and the lions, and step into the National Gallery while you are there.
Afternoon. Head to Westminster for Westminster Abbey and the Palace of Westminster, including the Elizabeth Tower. From there, cross to the South Bank for the London Eye and Tate Modern, and if you have booked ahead, the viewing deck at The Shard.
Evening. Finish in the City at St Paul's Cathedral, then walk to Tower Bridge and the Tower of London, which sit beside each other near Tower Hill. If you want a meal to close the day, the Tower of London has buildings on the property where you can eat, and Westminster Abbey has a restaurant and a café.
Frequently asked questions
Do London's museums charge for entry?
The majority have no entrance charges, which allows visitors to make multiple visits with ease. Special or temporary exhibitions usually attract an admission charge.
When can you tour Buckingham Palace and the Palace of Westminster?
Buckingham Palace is open for tours during the summer months only. Tours of the Palace of Westminster are available in July and August when Parliament is away on summer recess; otherwise it is open to the public only for viewing parliamentary debates.
What time is the Changing of the Guard?
It spans three locations — Buckingham Palace, St James's Palace and Wellington Barracks — and usually begins at 10:43. Check the published dates before you plan your morning around it.
How do you reach the main sights?
By Tube. The source material gives stations for each: Green Park for Buckingham Palace, Westminster for the Abbey and Parliament, Charing Cross for Trafalgar Square and the National Gallery, St Paul's for the cathedral, Tower Hill for the Tower of London and Tower Bridge, Waterloo for the London Eye, London Bridge for The Shard, and Southwark or Blackfriars for Tate Modern.
Pick the handful of sights that matter most to you, check the summer-only openings and the guard ceremony dates, and start building your days around the Tube stations above.