It either depends on their birthday (the day they were founded) or, like in the case of London, astrologers associate them with specific signs because the date of founding is unknown.
London is a really old city so no one really knows its birthday but astrologers strongly agree that London definetly is a typical Gemini city, representing the archetype and charecteristics of Gemini.
Gemini is the sign of teens and young adults, it stands for the vitality, flexibility and liveliness of youth.
London is definetly a place that young people feel drawn to and that is full of them!
Gemini is all about the latest trends and pop culture - just like London.
The whole world looks to London for fashion inspiration, music trends (especially the indie scene), etc.
Gemini is fast-paced and always changing.
This sign needs constant entertainment and mental stimulation because it gets bored easily.
Same with London: There's always something going on, the underground will get you anywhere, anytime quickly.
Gemini is the trickster - this sign hates being serious and they like to break the rules from time to time.
They love standing out, being a bit quirky and drawing attention to themselves.
London is known for their bold bright red buses and telephone boxes, and its where the punk scene originated.
London is a place of endless markets. Especially the markets where young people can sell their own art are typically Geminian.
In London, there are so-called pop-up shops - Shops that young entrepreneurs and artist can use for a few weeks to promote and sell their work, before another one takes over the little store.
This quickness and the constant changing, always having something new to explore pop up is a typical Gemini trait.
Gemini is the sign of the eternal student, always picking up new information.
London is full of schools and universities, museums as well as book shops and -markets.
Gemini isn't very serious about anything - definetly not about themselves.
It's a very self-ironic sign, which I personally feel, also applies to London.
Even though it's the city of the royal family and the capital of England, people there joke about themselves, the city, the weather, their slang, their culture and stereotypes all the time.
"A bad day in London is still better than a good day anywhere else."