One of Tower Bridge's immense cavernous chambers, lying below river-level, will become one of city's more unconventional music venues.
The south bascule chamber, normally out of bounds to the public, is being turned into a concert hall for the upcoming Totally Thames Festival.
Concert-goers will have to walk down 120 steps from bridge level to access the chamber. At the same time, performance timings could be rescheduled if the bridge needs be lifted, or in the event of a mechanical fault.
There will be six performances per day across the last weekend of September, between 11am and 6.30pm.
Each event will last one hour, and have capacity for up to 48 people, with tickets costing £25 per person.