A British band is squeezing into an airtight, soundproof box where it will perform until the oxygen runs out.
Death metal group Unfathomable Ruination give their first performance outside The Gherkin in the City of London at 6pm tonight.
But no one will hear it. The only hint of a performance from the outside will be some strange vibrations from the cube.
The band will emerge when they can't physically continue because they have run out of oxygen, and carrying on beyond that could prove lethal.
The performance is part of the City of London's 'Sculpture in the City' exhibition. The cube is an art installation by Portuguese artist João Onofre called 'Box Sized DIE'. According to organisers:
Performance times are 3 July at 6 and 7pm and 4 July-1 August 2014 at 6pm Wednesday to Friday. If you're wondering what the band sounds like, here's a taste of what will be going on inside.