Dear Amazon,

That little package you delivered last week to America's biggest cities was pure marketing genius, on par with your announcement about cutting prices at Whole Foods. Now you've got hundreds of municipal officials elbow-deep in the research necessary to find you a home for your second headquarters. You've launched the equivalent of Survivor: The Urban Edition, except in this version, the winner pays you.

The nation's urbanist pundits haven't wasted any time in handicapping the contestants. Before the first day's news cycle was over, the New York Times Upshot column had declared Denver the winner. The Brookings Institute's transportation guy likes Charlotte, N.C. Creative-class guru Richard Florida believes Washington, D.C., is the natural choice. Bloomberg reported that Boston has a lock on the contest.

These are all fine, lively places where I wouldn't mind spending a long weekend. But because you want a city where you can grow your company to 50,000 employees over the next 20 years, you need a home base that can hold your interest over the long term. It has to have a strong sense of place, a rich cultural life, great transit connections, and lots of infrastructure-ready land that is close to both the business center and top universities.

Let me suggest a location that has all these qualities and also has proven its appeal for 300-plus years: Philadelphia.

Although you didn't say this in your request for proposals, I'm guessing that you want a location that offers a different point of view from your current home in Seattle. The East Coast would provide that corollary, as well as a jumping-off point to colonize Europe. Denver is really a high-altitude version of Seattle, but with a more inconveniently located airport.

Your proposal smartly expressed a desire for the trinity of great urbanism: density, walkability, diversity. Of all the metropolises on the Northeast Corridor, none offers a better version of that mix, at a more affordable price, than Philadelphia. Where else can you have all the fruits of density and still live in a single-family home? Any home buyers you bring in from Seattle are going to have reverse sticker shock. We've got some great, transit-accessible suburbs, too.

I realize I'm biased, having migrated to Philadelphia three decades ago from a large-ish city 90 miles to the north. But this gritty-around-the-edges former manufacturing town is really a place where you can dig in, make a life, and be anything you want to be. It's an old city that is authentically authentic, yet crackles with youthful vigor. Our median age, 34.1, is among the lowest of American cities.

We've got millennials and makers coming out of the woodwork, which ensures a deep pool of talent to staff your headquarters. To be honest, we're not turning out quite as many software engineers as some of our competition, such as Pittsburgh. Historically, we've been more of a medical research and pharmaceutical town. But our marquee tech company, Comcast, hasn't had any trouble pulling in engineers or executives. Besides, like Comcast, you're about so much more than tech these days, judging by your owner's forays into the journalism, film, and grocery businesses.

Right now, Philadelphia's two top business promoters, Commerce Director Harold Epps and  Philadelphia Industrial Development Corp. president John Grady, are hunkered down, working full time to prepare a pitch laying out all the details, so they can make your Oct. 19 deadline. They've got a scouting trip to Seattle planned for later this month.

Dozens of other cities are doing the same. But this exercise in self-promotion is something new for us in Philadelphia. Two decades ago, when the city was on the ropes and its very survival in question, no one here would have dared to engage in this sort of public chest-thumping. It's not that Philadelphia didn't have its charms; it's just that the layers of neglect made them hard to see. But as the city has boomed with new construction and regained population and jobs — outpacing New York in the rate of growth, by the way — it has shed that inferiority complex. "We're really excited to tell that story now," Grady told me.

The city knows the competition is stiff. There isn't an American city these days that hasn't rediscovered its core and populated it with millennial precincts and high-design cafés selling $4 lattes. What's nice about Philadelphia, though, is that our downtown was never destroyed. It's the real deal, open to serendipitous juxtapositions of high and low, old and modern, soaring glass high-rises and toy-like Colonial rowhouses.

Philadelphia isn't one of those cities with one or two hot neighborhoods; it has dozens, each with its own distinctive identity and populated by committed old-timers and passionate newcomers. They may disagree about certain things, but they always end the discussion with a block party.

And speaking of parties, you won't find a more hospitable city. In the last three years, we've hosted the Democratic Party's national convention, the pope and the NFL Draft. All those millennials pack our downtown sidewalks and waterfront trails, and sometimes make it annoyingly difficult to get last-minute restaurant reservations on Saturday night.

Of course, Washington, Boston and New York have similarly eclectic centers, but they're pricey places because they're already chock-a-block with tech companies. I can imagine you might be tempted by Baltimore and Newark, N.J., which are more affordable and similarly connected by Amtrak. But Philadelphia's got the superior location, midway between Washington and New York, the nation's political and financial capitals. It's one reason why Forbes thinks we're the city to beat.

Better still, Philadelphia has a huge chunk of land next to 30th Street Station with more property than you could ever hope to absorb. That fledgling innovation district, called Schuylkill Yards, is walking distance to both Center City and the universities. And the land is controlled by a single real estate entity, which means no bidding war for property as your headquarters grows. Because we're upriver from the ocean, we can fairly confidently predict that the city won't be inundated by sea-level rise.

More than any of our competition, Philadelphia has size — twice as many people as Denver, Charlotte, D.C., or Boston, not to mention Seattle. Bigness brings a thrilling diversity. The "City of Brotherly Love" isn't merely a quaint old phrase we like to trot out. The mix has made us attuned to difference in a way that is crucial to the success of modern companies such as Amazon. No one is passing laws here restricting which bathroom people can use.

We know we have some weaknesses. No one likes the wage tax, and the city has been slow to cut it down to size. Philadelphia may be rich in architecture and culture but struggles to make ends meet. Our schools are underfunded, as with many places. We will never be able to offer you $1 million a head to locate your headquarters here, the way Gov. Christie did with Subaru in Camden. Anyway, cities that pay more than $50,000 an employee will never break even, according to Greg LeRoy, at Good Jobs First, a think tank that studies corporate subsidies.

But you're Amazon. You don't need the money. What you do need is a dynamic, well-connected, up-and-coming home. Whatever happens, the future belongs to this dense old East Coast city.

OK. So, now that we have that settled, can we talk about that all-cotton duvet cover I just ordered?

UPDATE: Philly one of 20 finalists for Amazon HQ2