When Swiss architects Herzog & de Meuron and Ai Weiwei were chosen to design this year’s Serpentine Gallery Pavilion, the occasion marked a decidedly glorious reunion (their last collaboration, the futuristic Bird’s Nest stadium for the 2008 Beijing Olympics, was an aesthetic marvel of architectural innovation and eco-friendly solutions). This week, the dream team revealed their design for the annual commission, fleshing out their original concept of exploring the history of the eleven prior pavilions designed by starchitects Zaha Hadid, Oscar Niemeyer, Rem Koolhaas, Frank Gehry, SANAA, Jean Nouvel, and others. Ai is working with Herzog & de Meuron (whose facelift of Tate Modern is well under way) via Skype, as his fight against the Chinese government’s politically-motivated tax evasion charges prevents him from leaving Beijing.

The trio’s design pays homage to the former pavilions by erecting eleven columns five feet beneath the lawn of the Serpentine, plus a twelfth that supports a floating platform roof that hovers above the recessed floor space. The roof, simulating an archeological dig, collects rainwater to create a reflective surface, which can be drained to form a dance floor or event space.

For the interior, Ai and Herzog & de Meuron embarked on an actual excavation, burrowing into the park’s soil like archeologists to uncover fragments and imprints of past pavilions. The layered pattern of circles, dots, and cavities they discovered were then reconstructed into a comprehensive three-dimensional landscape, which is clad in cork to emphasize the excavated effect. Visitors can sit, stand, or lie down in the space.

The structure marks the team’s first collaborative build in the UK and will be part of the London 2012 Festival, a twelve-week-long art extravaganza coinciding with the Olympic Games. After it closes in October, the pavilion will become part of the private collection of steel magnate Lakshmi Mittal, who jumped at the chance to snatch up the project.

UPDATE: Word has it that after the excavation began last week, the foundations of pavilions past do not actually exist. Apparently, wrapped up in the excitement of the initial design process, somebody forgot to tell the Swiss-and-Chinese posse that all remnants from prior pavilions have been completely removed from the site. The only thing left of any distinctive foundation is of the usual soil and rocks kind. The designers, however, remain steadfast in their vision, and have embarked on the deed of manually overlaying plans from the past eleven pavilions to come up with a new shape for their pop-up block.