London's Doors Open Wide: Open House Festival Set for 12-20 September

London's celebrated Open House festival, which throws open the doors of the city's architecture to the public, will run from 12 to 20 September in 2026. Founded in 1992, the festival has grown into a fixture of the capital's cultural calendar, typically drawing around 250,000 people eager to explore buildings they would otherwise never see inside.

This year's highlights include several of the festival's most requested regulars: 10 Downing Street, the BT Tower, and BBC Broadcasting House all return to the programme. Two buildings by architect Richard Rogers also feature prominently—Lloyd's of London and 22 Parkside. According to London the Inside, the Lloyd's Building, a defining example of High-tech architecture, carries particular significance this year as it opens its doors as part of celebrations marking its 40th anniversary.

The same outlet also reports that among the notable additions to the 2026 lineup is the Zaha Hadid Foundation archive, said to be appearing in the Open House programme for the first time. Its inclusion offers visitors a rare opportunity to engage with the legacy of one of architecture's most influential figures through primary archival material.

For attendees planning their visits, organisers have confirmed that more than 500 buildings will be accessible as drop-ins, meaning no pre-booking is required to walk through their doors. This flexibility allows festival-goers to move freely between sites across the nine-day event, making it easier to fit in the buildings that catch their interest as the week unfolds.

Open House continues to serve as one of the few chances each year for Londoners and visitors alike to step inside the city's architectural landmarks, from historic institutions to contemporary landmarks.