Great Conservatory

And a bird, at Syon Park, Brentford. Not black and white, so I left the top of the gate in as evidence.

From the syonpark.co.uk website:
The crowning glory of Syon Park's gardens is the Great Conservatory. The 3rd Duke of Northumberland commissioned Charles Fowler to build a new conservatory in 1826, the first of its kind to be built out of gunmetal, Bath stone and glass. It was originally designed to act as a show house for the Duke's exotic plants and inspired Joseph Paxton in his designs for the Crystal Palace.