The phrase "alien city" is correct and usable in written English.
It can be used to describe a city that is foreign, unfamiliar, or otherworldly, often in a science fiction or fantasy context.
Example: "As the spaceship landed, the crew gazed in awe at the alien city that sprawled beneath them, with its towering structures and vibrant colors."
Alternatives: "foreign city" or "extraterrestrial city".
For a greenhorn, the traffic offers a novel perspective on an alien city.
So you've just arrived at a completely unfamiliar alien city on an unknown planet at any possible point in time.
Embassytown is a human diplomatic enclave in the middle of an alien city on Arieka, a planet at the outer edge of the known universe.
In the 1968 essay "An Alien City," he recalled his boyhood impression of Jerusalem's inhabitants: "A taciturn, sullen race, always seemingly quelling an inner dread.
In the dead of night, in spite of the electric lights, London seems an alien city, especially if you are walking through it alone.
It presents Anthony as a mysterious blend of canny intuition and near-Martian naivety as he wanders the alien city – his perceptions are fresh, melancholic, original.
Confronted by alien cities, villagers tried to recreate those enclaves.
In alien cities we'll / remain, like trees, like stones".
"It's very unlikely that there are alien cities on the edge of our solar system, but the principle of science is to find a method to check," said Turner, who has focused on numerous topics in theoretical and observational astrophysics, including large-scale structure, dark matter, exoplanets and astrobiology.
Newcomers to the city have found their way to The Green Backyard somehow; it's a place where they can socialise, integrate, and where they can find their feet in what must be a really alien and foreign city.
He says the aliens' cities were washed away in a great flood 30,000 years ago, after which they began passing on their knowledge to humans.
