Four free museums between Holborn and Marylebone

None of these charges for the permanent collection, and all four are in the middle of town. The Grant does not open until 1pm, so we would do the Soane or the Wallace in the morning, have lunch, then walk up to Bloomsbury for the afternoon.

Sir John Soane's Museum, Lincoln's Inn Fields

The house of the Regency architect Sir John Soane, kept by Act of Parliament exactly as he left it when he died in 1837. He knocked three townhouses together and filled them with antiquities, plaster casts, Hogarth's A Rake's Progress hung on folding walls, and the alabaster sarcophagus of Seti I in the basement. From the square it looks like a private house, with no real signage, which is why most people walk past. Free, walk in, no booking. Open Wednesday to Sunday, 10am to 5pm. The rooms are small and there is a capacity limit, so go at 10am on a weekday or after 3.30pm and avoid weekend afternoons. Free tours of the private apartments run at 2pm on Wednesday, Friday and Sunday, first come first served. Holborn is five minutes' walk.

Grant Museum of Zoology, Bloomsbury

One of the last surviving university zoology museums, in use for teaching since 1828 and open to the public since 1996. It is one Victorian room holding about 100,000 specimens in jars and on shelves: the jar of moles, quagga and dodo remains, a wall of brains. Small, dense and genuinely odd, inside a UCL building on a side street with none of the marketing of the big Kensington museums. Free, no booking. The catch is the hours: Tuesday to Saturday, 1pm to 5pm only. It is in the Rockefeller Building on University Street, two minutes from Euston Square. The Petrie Museum of Egyptian archaeology is a few minutes away on Malet Place with the same hours, if you want a second one.

Wellcome Collection, Euston Road

A free museum and library about health and the human experience, built on the pharmaceutical magnate Henry Wellcome's collection, directly opposite Euston station. There is a permanent gallery, Being Human, big temporary exhibitions that change through the year, and an upstairs Reading Room where you can sit with a book or a coffee for as long as you like. Everything, including the temporary shows, is free. From the pavement it reads as an office block, so people walk past it on the way to the British Library. Galleries open Tuesday to Sunday, 10am to 6pm, closed Monday; the late Thursday openings have ended, so do not plan on an evening. Euston Square is three minutes' walk.

The Wallace Collection, Manchester Square

Hertford House was the London home of the Marquesses of Hertford, and it is now a national museum holding what they collected: Frans Hals's Laughing Cavalier, Fragonard's The Swing, Rembrandt, Velázquez, Sèvres porcelain and four galleries of arms and armour. It is seven minutes from Bond Street station, behind Oxford Street, and most people shopping there never realise it is that close. The glazed courtyard restaurant is our rainy-day lunch. The permanent collection is free and you walk in; the special exhibitions are ticketed. Open daily 10am to 5pm. Weekday mornings are quietest, especially the Great Gallery upstairs before noon.

• Sir John Soane's Museum: Wed to Sun 10am to 5pm. Free, walk in. Holborn 5 min.
• Grant Museum: Tue to Sat 1pm to 5pm. Free, no booking. Euston Square 2 min.
• Wellcome Collection: Tue to Sun 10am to 6pm. Free, no ticket. Euston Square 3 min.
• Wallace Collection: daily 10am to 5pm. Permanent collection free. Bond Street 7 min.
• Suggested order: Soane or Wallace at 10am, lunch, the Grant from 1pm, then the Wellcome until 6pm.