A painting by Italian master Canaletto is expected to fetch £5m when it goes under the hammer in London in July.
The auction will take place in London on 5 and 6 July
The View of the Molo, Venice, will be part of a £15m auction of items owned by Portuguese businessman Antonio Champalimaud, who died last year.
The painting shows the Doge's barge, the Bucintoro, with crowds on what is thought to be Ascension Day, when the Doge blessed the city.
It was the "undoubted star" of the auction, Christie's said.
The Molo, or wharf, was a favourite view for Canaletto, but Christie's said this painting was "unique in its vertical format and its viewpoint".
Canaletto, real name Giovanni Antonio Canale, lived from 1697 to 1768.
He became famous for painting views of the buildings and canals in his native Venice.
The auction will take place on 5 and 6 July and will also include other paintings, sculpture, furniture and Chinese porcelain.