"A Tale of Two Cities" is a good example of how a megacity can be a perfect setting for a novel. Life, death, comedy, tragedy, joy and sorrow are all heightened here. Charles Dickens would know too well while he described Victorian London. As for Paris, he captured the intensity behind the pre-revolution capital. It won't be possible with a remote location (and there would be many titles to prove it). Could it be the same on the big screen? Of course.
Gotham, for instance, could fit the description. Bruce Wayne felt it, as his facial features would show it. The villains snapped out of it. (Tim Burton showed how Catwoman got fed up with the system.) Fritz Lang might have illustrated the most unlikely outcome, a futuristic community operated by an underground of slaves. It was more like a setting of a H.G. Wells novel, but this won't be the right place for debate. There could be other places. (Someone may mention Lagos. The largest city in Nigeria would appear in a Marvel film for ten minutes or so.) Let's check out the other megacities:
London (Bram Stoker's Dracula). There could be other movies that would describe the British capital, but this classic Gothic novel fit like a glove. London was too old, and there were lots of stories to tell anyone, everyone. If authors (or filmmakers) were drawn to the sinister aspects, then they knew this tale would be incomplete without it. Otherwise, you don't know your Hammer (or Amicus).
New York/Los Angeles (I Am Legend). If you're too old (or have seen too many films), then you'll cite "The Last Man on Earth". If you're a Charlton Heston fan, then you prefer "Omega Man". The most recent version of Richard Matheson's novel was set in New York, which was a ghost town. But the sun hasn't set down. A virus turned the populace into vampires, and they would come to Neville's house every night. New York and Los Angeles, the original setting of the book, would be worlds apart, but the silence could be deafening. Neville got used to solitude, but he couldn't face an eternity by himself. Life would be found in the shadows.
Mumbai (Slumdog Millionaire). Danny Boyle's dazzling shots turned Mumbai into an electric dream. The bright colors might mislead moviegoers especially those who have set foot in the Indian subcontinent, but this was the allure of cinema. The British filmmaker highlighted the poverty that would define one of the largest cities in the world, which didn't seem bad to look at. It could be attitude, if not an open mind.
Rio de Janeiro (City of God). Hollywood saw a favela as a caper while Brazilian directors like Walter Salles saw a path to salvation. This chronicle of young boys who grew up in the slums of Rio de Janeiro sent a clear message. There won't be a Brazil without this so-called eyesore. Tourists may prefer the Copacabana (or Christ the Redeemer), as they were warned about venturing into the favela. But they might be missing something. They won't do a Carmelo Anthony (on Instagram).
Rome (Federico Fellini's Roma). Viewers would be hypocrites to keep a distance from this capital, where there was hardly any dull moment. Anna Magnani would know it while walking the cobbled streets (in Pier Paolo Pasolini's classic drama). The clerics weren't holy as the people would know while melancholy lurks behind the Roman temples. No one couldn't take a pick.