Image: The Serpentine Gallery Pavilion 2012

The Serpentine Gallery in London has unveiled the Herzog and de Meuron/Ai Weiwei-designed Pavilion - the 12th commission in the contemporary art attraction's annual series.

This year's Pavilion - part of the London 2012 Festival - enables visitors to go beneath the Serpentine lawn to explore the "hidden history" of the gallery's previous 11 commissions.

A total of 11 columns represent previous structures, while the 12th supports a floating roof 1.4m (4.6ft) above the ground. Design features of the Pavilion include cork cladding.

International spa company ESPA is sponsoring this year's Pavilion, which is operating as a public space and as a venue for the gallery's Park Nights programme of events and talks.

Serpentine Gallery director Julia Peyton-Jones and co-director Hans Ulrich Obrist said: "It is a great honour to be working with Herzog and de Meuron and Ai Weiwei, the design team behind Beijing's superb Bird's Nest Stadium."

The Pavilion will remain open until 14 October.

Details: www.serpentinegallery.org

Image (c) Herzog and de Meuron and Ai Weiwei/Image (c) 2012 Iwan Baan