The city of Mumbai, India, is home to nearly 14 million people.
To put that number in perspective, it's like more than the total population of Illinois all packed into an area smaller thanChicago.
And that's not counting the estimated 10 million more people that live in Mumbai's sprawling suburbs. In parts of the city there are more than 1 million people per square mile -- more than any other spot in the world.
"It's just like the whole city is like alive and kickin'," Pooja Batra, former Miss India, told "Good Morning America." "It has an essence. It has a heart. It has a character."
To keep the heart of the city beating, Mumbai sports an impressive infrastructure, including one of the world's largest network of trains and shuttles that carries more than 6 million people daily.
The seaside city is also the nerve center of India's economy and workplace to thousands of business people.
Lunchtime is a spectacle of human logistics.
Then, 5,000 men who call themselves "tiffinwallas" deliver 175,000 lunches to working people in Mumbai each day using a unique and complicated conveyor-beltlike system. The tiffinwallas also use bikes, buses and trains to get home-cooked meals perfectly sorted and shuttled through Mumbai traffic to their customers.
Even though the effort is massive, the tiffinwallas purportedly make mistakes only once every couple of months.
Such attention to accuracy earned the tiffinwallas a Sigma Six rating from Forbes, the biggest worldwide prize in efficiency.
Efficiency is not the only reason Forbes has taken notice of Mumbai -- the city is also home to 20 of the world's billionaires.
But alongside the vast richness and luxurious lives of India's elite is the extreme opposite -- utter squalor in the city's crumbling slums where more than half the city's population lives.
There, the rich literally live on top of the poor. Million-dollar condominiums are stacked on top of shantytowns.
It is a symbolic image for the many who live below who dream of being one of the few who live above.
In a country where so many are lacking, novelist and actress Shobhaa De has led something of a charmed life.
"My world, unapologetically I suppose, is the world of the elite in India. It is a privileged world," De said. "But that does not mean that one doesn't have a conscience and one cannot do something with that privilege. And I try my best."
De referred to Mumbai's massive poor population housed in the cities sprawling slums.
"That's what makes the city so challenging because you have to live beyond that all of that. Here we deal with it. We have our poverty. I'm not saying we deal with it very competently, but we are not in denial about it."
Dev Tank, 22, is not in denial about it at all. He lives in Dharavi, Asia's biggest slum, with more than 1 million people. There, where his family has lived for three generations, most people do not have clean water.
But Tank does not call his home a slum.
"It's more like a community living together, helping each other," he said.
Of course, Tank does not seem like someone who would generally live in a place like Dharavi. He is a college graduate and has a good-paying job at a multinational financial firm.
"If you're not educated, you cannot do anything," Tank said simply.
But he still lives in Dharavi with his three sisters and their parents in a small home, all six sleeping in one room. He makes enough money to move out, but said he would not, because the home has been in his family for so long.
His co-workers do not know where he lives, Tank said, because they would judge him based on his address. But Tank said he knows better.
"I know that I'm much more different from people who live here," he said. "Even in a slum you find people with very good determination who want to come up in life."
In a symbolic triumph of that dream, Mumbai-based international sensation "Slumdog Millionaire" swept through Hollywood's Academy Awards this year.
But long before "Slumdog," India was no stranger to the silver screen.
Hollywood may be America's home for silver screen stars, but halfway around the world in India, Bollywood is the name of the game. Where Hollywood may produce around 600 movies a year, Bollywood generally puts out double that number.
To produce all those movies, India is home to a 2,500-acre film studio -- the largest in the world.
"Many, many more people watch Bollywood than Hollywood," author Suketu Mehta said. "It is the world's most successful popular art form."
By some counts, nearly a billion more people watch Bollywood films than Hollywood films.
All those people are connected through watching the films, one Bollywood star said, because they tend to deal with universal themes.
"They depict passion. They depict determination. They depict anger," actress Preity Zinta said. "And that with the backdrop of Indian culture and ethics."
Most of the films use a tried and true formula, one audiences have come to expect.
"Bollywood is, simply put, song and dance," Batra said. "It's fantasy, going to this fantasy land of beautiful women and the guy dancing, serenading and getting the girl."
To Anumpama Chopra, a film critic for New Delhi Television 24/7, Bollywood offers something Hollywood has forgotten.
"There's a lot of goodness, truth, honor," Chopra said. "You know all of those things that are harder to find now in Hollywood films. And it's very old fashioned storytelling."
After the wild success of "Slumdog Millionaire," Hollywood is reportedly chasing Bollywood.
Tom Hanks, Will Smith and Brad Pitt are reportedly exploring Bollywood productions.
"A lot of Hollywood actors are working in Bollywood movies. A lot of Bollywood actors are working in Hollywood. And rightly so. Why not?" Batra said.
Anil Kapoor took his first international role in "Slumdog Millionaire," starring as the game show host, but he's a well-known Bollywood star who said Hollywood is giving Bollywood a little more respect these days.
"When I was in L.A. I met quite a few filmmakers and I've already got four scripts," he said. "They want to shoot films in India."
And it's not just Hollywood that has perked up its ears. In France Bollywood stars are very popular; in Russia, Bollywood styles are stealing the fashion scene.
"Indian movies have made their own niche all over the world," Batra said. "I mean, be it Middle East, be it Europe, Russia, everywhere. Everywhere you go people are watching Bollywood movies. And they love it."