Under the cover of one of the world’s most individual contemporary structures, a show of a different kind is being staged. The arena which has been designed and constructed inside ‘The O2’ (formerly the Millennium Dome) forms the focus of an entertainment destination. An extensive range of music and sporting events have been staged since it opened in early 2007, hosting more than 150 events in its first year of opening, making it the UK’s premier venue. The innovative design of the arena responds to its unique context within The O2, through an architectural approach focused on the experience of the users. With the event space and seating bowl forming the heart of the building, the public concourses and suite levels wrap around this core, and focus outwards into three main atria which address the internal levels of the building. The combination of judicious material selection and dramatic lighting emphasises the scale and volume of the public realm. This is no more dramatically explored than in the triple height O2 blue room, where set against a backdrop of a 30m wide by 7m high projection wall, 500 visitors become central to the experience, interacting with their environment through the latest technology. A backdrop of clean architectural and graphic expression acknowledges the differing individuals who will attend the variety of events it holds, through a mix of bars, private lounges and food concessions. The logistical challenge of placing a building the scale of the arena, within the Dome necessitated that the roof would have to sit tightly beneath the Dome liner fabric, whilst maintaining a minimum 4-metre separation for air and smoke reservoir provisions. Emergency exiting and fire / life safety considerations for the Arena will build upon approved solutions developed originally for the Dome. The innovative structural methodology required to erect the building cores and enormous roof system without conventional tower cranes lends itself to the fitting analogy of building a ship within a bottle, albeit at the largest scale imaginable.