16 unique buildings to see during London Open House 2026

Once a year, Christmas comes early for explorers of London architecture and history. For nine days, buildings that are normally closed to the public, guarded by security, or simply invisible from the street throw their doors open, free of charge. That’s Open House London, and it’s one of the best excuses in the city’s calendar to go somewhere you’ve walked past a hundred times and never actually seen inside. This year’s Open House festival runs from 12 to 20 September 2026, with bookings for ticketed tours opening at midday on 19 August (mark your calendar, some of these go fast). Below are 16 of my picks: a working Victorian pumping station still running on beam engines that are the last of their kind in the whole world, a London icon about to vanish into a seven-year renovation and emerge as something else entirely, an archive that’s been quietly documenting the darkest chapter of the twentieth century since it was still unfolding, and more. Some are grand. Some are strange. All of…