Venice

Venice was a city in Italy on the Adriatic coast. (BFA: The Stones of Venice)

History
Originally a collection of huts built on marshland by people running from Atilla the Hun, it grew into, according to the Eleventh Doctor, "one of the most powerful cities in the world". Influenced by a variety of cultures, it was the hub of a trading empire, its islands famously separated by an intricate series of canals. By 1580 it already had a population of some 200,000 people. Because of its improbable architecture at or below sea level, it was gradually sinking over time.

Marco Polo was born in Venice. (DW: Marco Polo)

The Eleventh Doctor, Amy Pond and Rory Williams visited Venice in 1580, a colony of Saturnynian refugees made it to Venice in 1580, led by Rosanna Calvierri along with her children. Only the male children seemed to survive, though there were 10,000 of them. To rectify this problem and save their species, Rosanna lied about an outbreak of the plague, quarantining the city. She then began a process where they took in young girls under the pretense of providing them a better education. However, once amongst them, Rosanna and her son would drain them of blood and replace it with Saturnynian blood, converting them into Saturnynians. Rosanna also intended to to create a tidal wave that would sink the city of Venice, providing them a habitat to live in. Their actions unwittingly brought the attention of the Doctor, Amy and Rory after they took in Isabella. They and Isabella's father, Guido, investigated the school, enrolling Amy to help them get him. Though she was able to open the trap-door, she was later captured. With the help of Isabella, they were able to escape, though Isabella was dragged back and later killed for insubordination. Rosanna sent the converted females and her son Francesco to stop them, while starting the process to sink Venice. The females were all killed when Guido blew up the house when they attacked, while Francesco was killed when Amy directed sunlight on him. The Doctor was also able to disable the device. With her species doomed and her plans stopped, Rosanna killed herself by jumping into the water with her perception filter still on, with her children not knowing who she was and feeding on her. (DW: The Vampires of Venice)

The First Doctor, Steven Taylor and Vicki visited Venice in 1609, where he told them that it had disappeared into the ocean "centuries before either of [them] were born". (MA: The Empire of Glass) However, it was Eighth Doctor who actually witnessed the demise of Venice. In the 23rd century, it finally succumbed to the weight of its illogical design, and disappeared into the lagoon from whence it had originally come. (BFA: The Stones of Venice)

Reputation
At least three personas of the Doctor found it an incredibly attractive city to visit. The First Doctor once told Steven and Vicki that the marshes immediately surrounding the city was a "wonderful place", primarily based on the quality of the air and shoreline. (MA: The Empire of Glass) The Eighth Doctor told Charlotte Pollard it was "magnificent and charming and often quite silent and sinister", and a city with a desolate look in the morning that was reborn by its own lights every night. (BFA: The Stones of Venice) The Eleventh Doctor took Rory Williams and Amy Pond to the city as a wedding present. He described it as an "impossible" and "preposterous" city "constantly being invaded, constantly flooding, constantly . . . just, beautiful". He was confident Amy and Rory would love it because many famous humans before them — including Byron, Napoléon Bonaparte, and Casanova — did. (DW: The Vampires of Venice) On two occasions, Venice has been visited by aliens which had technology to allow them to appear human to the Venicians, the Saturnynians (Perception filter) and the Jamarians (Hologuise Generators).