From the River Thames to Greenwich and Richmond, from South Kensington's museums to the Tower of London, there are free sightseeing adventures for visitors and locals.
London is easy to love but can be hard to afford. With a little research and planning, you can find unusual excursions that won't cost you anything beyond the fare.
London is best seen on foot, but what if you don't know your way around? Go online before your trip and print out one or more of Richard Jones' free walking tours. Jones is an author and guide with over 25 years' experience of planning tours. The free walks cover many of London's famous names and places, from Dickens to Jack the Ripper and from Windsor to the East End.
You can also download free iPhone tours, maps and audio guides from companies including London Travel Guide and iAudioguide.com. Several companies, including Sandemans and The Original London Sightseeing Tour, offer free guided walking tours, and Original London customers can currently get a free river cruise if they buy a bus tour ticket. Check websites for details.
The Changing of the Guard is a tourist staple and not to be missed. The Ceremony of the Keys at the Tower of London (Tower Hill Underground) is much less well known. Every night at 9.30 pm, the Yeoman Warders make a centuries-old ceremonial patrol and lock the outer gates of the Tower. You have to book three months in advance, but you'll see the Tower at dusk and miss the huge daytime crowds. Apply in writing for your free tickets to Ceremony of the Keys Office, Tower of London, London EC3N 4AB, UK, giving the names of all attendees, two possible dates, and enclosing a self-addressed envelope with a British stamp or two International Reply Coupons.
Watch the machinery of Government in action with a visit to the Palace of Westminster, home of Parliament. Debates in the House of Commons and House of Lords are open to the public when the House is sitting, check here for access details. Afterwards, nearby Victoria Tower Gardens offers a lovely setting for a picnic lunch and a view of Rodin's great sculpture The Burghers of Calais.
London's great museums - the British Museum, the V&A, the Natural History Museum - are world famous, but there are scores of smaller museums with much to offer. Sir John Soane's Museum in Lincoln's Inn Fields near Holborn Underground, is the private collection of the man who built the Bank of England, shown in his own home, open Tuesday-Saturday, 10am -5 pm.
The Museum of London on London Wall is currently being redeveloped but the four open galleries are packed with information. Near Barbican and St. Pauls Underground, it's open Monday-Saturday 10am-5.50pm, Sunday noon-5.50.
The Wallace Collection is located in elegant Hertford House on Manchester Square, near Bond Street and Baker Street Underground. It offers a glimpse of gracious living Georgian-style as well as wonderful art, open daily 10am-5pm.
The Geffrye Museum on Kingsland Road near Old Street Underground opens Tuesday-Saturday 10am-5pm and offers a window into English domestic life from 1600 to the present, with beautiful gardens.
You can visit the Central Criminal Court at Old Bailey, near St. Pauls Underground, and if a trial is in session you can watch from the public gallery, Monday to Friday 10am-1pm and 2pm-5pm. The building dates from 1907 and has survived German and Irish bombs, but the first court on the site was built in 1539. On the corner of Old Bailey and Newgate Street is the site of the 12th century Newgate Prison, demolished in 1902. Opposite is St. Sepulchre's Church where prisoners prayed over their open coffins before execution.
The Royal Opera House, the Barbican Centre near Barbican Underground, the National Theatre near Waterloo Underground, and many other venues offer free concerts and exhibitions. Some of London's many churches also offer free music. Times and performers vary so check out their websites.
There are a huge number of child-friendly venues with no admission charges in London. Check here for more details. Anytime of year children can pet animals on a city farm, run around in parks or go on a dinosaur trail. A little forward planning and online research will give you lots of ideas for specific times - free concerts, craft workshops, storytelling sessions and nature walks are arranged at many venues.