
Ornate Victorian pumping stations, an oak-panelled board room, and a pint-sized museum of antique televisions are all accessible, as part of this years Heritage Open Days.
Running from 9-18 September across the UK, Heritage Open Days invites urban explorers into nooks and crannies of the country that are often off-limits.

This year's theme is 'Astounding Inventions' and London highlights include:
- Pumping stations/'cathedrals of sewage' at Abbey Mills, Streatham and Enfield.
- The 17th century oak boardroom carved by Grinling Gibbons, and now owned by Thames Water.
- A place we once suggested might be the best shed museum anywhere, Dulwich's British Vintage Wireless and Television Museum.
- 13 Princelet Street — a chance to step inside one of Spitalfields' gorgeous Huguenot houses (warning: may trigger house envy).
- There's also a slew of guided walks, including Harefield Canal, Mitcham Cricket Green, Kingston, and a chance to learn about the inventors buried at Willesden Jewish Cemetery.
All are free to visit/do, but you'll need to book in advance. Booking for different venues opens/closes at different times — your best bet is to peruse the calendar, earmarking the places you're keenest to visit.
September is a bonanza month for those eager to do a deep dive into London; the Open House festival also runs 8-21 September.