Because Manhattan has long been a center of world commerce, it has drawn immigrants from the world over since its founding.
By 1900, people and money had gobbled up the 22 square miles of the island. Prevented from moving out, the city moved up.
The island of Manhattan is essentially one big rock. With solid mooring inches beneath the topsoil, the only limit on the heights of buildings is the ever-improving strength of building materials.
For the eight decades from 1890-1974, the tallest building in the world was in Manhattan.
The narrow spire of the now-defunct Singer Building pierced the skyline in 1909. It was superseded by the Met Life Building in 1910.
In 1913, the stunning Woolworth Building, which still stands in 57-stories of ornate gothic splendor, was completed and held the title of world's tallest building until the glistening Chrysler Building took over in 1930.
The Chrysler Building's hold on the top spot lasted one year. Once the Empire State Building was finished, it stood as the tallest building in the world for the next 40 years.
Since then, hundreds of lesser but still impressive buildings have crept up in height on Manhattan's bedrock.
The result? More and more people who live and work high up compete for space down on narrow streets and sidewalks that were laid out in the 1800s.
"First we shape our buildings, then they shape us," Winston Churchill said in 1943. Nowhere is that more apparent than in Manhattan.
Sheer shortage of space defines life on the island.
The average price of a hotel room in the city is $247. For that amount, don't expect any leg room on the other side of the bed. Or a tub.
If you want an apartment, you have to buy one. Average price in 2007: $1.4 million per unit.
If you are silly enough to keep a car, you pay an average of $6,000 per year to park it. Recently, the New York Times reported the sale of an apartment parking space for $225,000.
The space squeeze doesn't just affect prices. It shapes the culture of the city.
Slip out the door of your hotel and you are immediately buffeted by the hordes. As the honks of the taxis echo through the concrete canyons, you elbow for space on the crowded sidewalks.
Rich smells, from the foul smell of sour milk to the delicious smell of ethnic foods, bombard your nose.
New Yorkers seem immune to both.
In fact, they are willing to spend $250 for lunch while sitting with their elbows tucked in at a tiny little table on the sidewalk only six feet away from a pile of garbage awaiting pickup.
Shortage of space breeds tremendous efficiency. Nowhere is efficiency more evident to the visitor than at a New York deli.
"Whatdayawant?" comes the yell from behind the counter seconds after you enter. The experienced yell their order back right away. The inexperienced get pushed to the side.
The second day, I qualified as experienced. I yelled "ham and cheese omlette,"
"Four minutes," he hollered, and I got in line to pay.
Four minutes later, I walked out lugging a massive omelette. I ate it off a little hospital style rolling table while sitting on the bed in the hotel, elbows tucked in.
So why do 1.7 million people live jammed on the little island.Why do another 44 million people visit each year?
The answer, I think, is obvious only after you've spent a day on the streets of New York. Worn to a frazzle, you stumble into your hotel room, take off your shoes, rub your blisters, lay back on the bed and stare at the ceiling.
Then, like a kid at the county fair who goes over and over on a ride that tosses him around like a rag doll, you say, "That was fun!"
By morning, you say, "Let's do it again!"