Can you identify this building to win a £25 drinks voucher?

You can walk along between the two leafs of this window wall. But what is the building?

Email your answer to First correct answer wins. The editor’s decision is final. No cash alternatives will be offered. No employees of CMP Information or their relations may enter.

The building on 31 October was Santiago Calatrava’s opera house in Tenerife, completed in 2003. The winner was James Chambers of Powell Dobson Architects