Palladian Bridge: Prior Park Landscape Garden
There are, according to The National Trust only four Palladian bridges remaining in the world. They don't mention which they are. I knew that three are in England, Prior Park, Stowe and Wilton and have found (thank you reddawnl) that the fourth is in the grounds of Catherine Palace near to St. Petersburg.  Although I visited the palace I unfortunately didn't see the bridge.
Created in the 18th century by local entrepreneur Ralph Allen, with advice from 'Capability' Brown and the poet Alexander Pope. The garden is set in a sweeping valley where visitors can enjoy magnificent views of Bath.This is a copy of one at Wilton built by Robert Morris in 1736.

<a href="http://www.nationaltrust.org.uk/priorpark/" rel="noreferrer nofollow">www.nationaltrust.org.uk/priorpark/</a>
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