WARNING: Spoilers ahead!

"It looks like a sad person lives here, and what happened to him? He got divorced, spilled red wine on the carpet, and didn’t care enough to clean it up." —Melanie, Don Draper's real estate agent

Episode 10 in Season 7 of "Mad Men" opens with Melanie, a perky real estate broker, entering Don Draper's now barren Park Avenue penthouse. After rousing him from bed and moving the patio furniture back to its rightful place on the terrace, she confronts him about the shabby state of affairs in his formerly swanky pad.

It turns out, Don's not a big believer in home staging—the adman even gives his agent a spiel on how to sell the place for its 1970 list price of $85,000(!). And despite 17B's hollow appearance and reek of failure, the episode concluded with the sale of the home. Ah, the end of an era in Don's life. With four episodes left to go, who knows where will Don wind up?

Seeing Don at this turning point inspired us to take a look back at where he—and his co-workers and girlfriends—have been. With the help of Max Galka, a data scientist and founder of Metrocosm, we narrowed down the locations of our favorite "Mad Men" characters' homes throughout the years and tapped into historical data to estimate the real estate values of then and now.

So loosen that skinny tie, pour yourself a drink, and join us in our tour of the homes of "Mad Men."

Don & Betty's suburban NY home

Address: Bullet Park Road in Ossining, NY

1960 estimated value: $30,000

2015 estimated value: $500,000

The home where we saw Don at his most suburban seems like a distant memory. But this standard (some might say bland) abode was just a façade. The Draper family wasn't enough to satisfy Don's ever-wandering eye, so we left this quintessential family home behind at the end of season 4.

The home was located in Ossining, a small town in Westchester County (the most affluent of New York's suburbs). It was the antithesis of the hustle and bustle of the big city: wide streets and tasteful homes with none of the rough edges of NYC.

While we remember the wood paneling and the ennui, this wholesome, All-American home in the Chilmark neighborhood also proved to be a great return on investment. In 1960 the Draper home would have sold for about $30,000 (the Census' median home value), Galka said. Today it would be worth about $500,000.

Don and Betty Draper's suburban home

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Don’s single-guy pad in Greenwich Village

Address: 104 Waverly Place, Apt. 3B

1964 estimated rent: $200–$300 per month

2015 estimated rent: $4,500–$5,500 per month

So much sadness in this seedy bachelor pad from Season 4. So much liquor and loss.

Now divorced from Betty Draper and mourning the loss of Anna Draper, Don takes up residence in this grim Greenwich Village apartment, within spitting distance of Washington Square Park. This is where we see an introspective Don who's trying to curb his drinking and writes in a journal to collect his scattered thoughts. In 1964, Don would have paid $200 to $300 per month in rent, Galka said, and $4,500 to $5,500 today.

Washington Square Park AMC

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Don and Megan's Upper East Side pad

Address: 783 Park Avenue, Apt. 17B

1965 Value: $55,000

2015 Value: $5 million

Perhaps the most iconic home featured in the show, this swanky penthouse was the backdrop to several jaw-dropping scenes, including Megan Draper's famous “Zou Bisou Bisou” dance and the time Sally Draper caught her dad cheating with neighbor Sylvia.

As difficult as it's been to tear our eyes away from these scene-stealers, it's also been tough not to gawk at the plush penthouse with all its appropriate Mid-Century trappings. The stylish décor and attention to period detail have earned raves from folks who want to re-create the look.

"People are influenced by pop culture all day, every day, and a very popular show like ['Mad Men'] based in New York is a big influencer," said Ryan Serhant, star of Bravo’s “Million Dollar Listing New York.”

"It's hard to find," Serhant said. "Everybody wants that type of apartment."

When the couple bought the Upper East Side apartment in 1965, home values had already increased significantly from 1960. A two-bedroom apartment in this location would run about $55,000 in 1965, Galka estimates. (The folks at Brick Underground were shocked that Don's apartment sold for only five figures, but given a mounting recession and the condition of the neglected penthouse, they say it's plausible.)

Today, the fictional abode would enjoy a location in the poshest part of the Upper East Side. (Nearby 740 Park Avenue, roughly a block away, has been called a "billionaire hive" and the "world's richest apartment building.") Don and Megan's apartment might not reach that kind of elite status today, "but a price tag of $5 million today would not be a stretch," Galka said.

Our friends at Gothamist crunched some numbers and figured out that Don, who was highly paid, wouldn't be able to afford this penthouse today. It makes that scene with Melanie the real estate agent just that much sadder, eh?

Don and Megan Draper's Upper East Side penthouse

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Peggy’s Upper West Side brownstone

Address: Unspecified

1968 estimated value: $25,000

2015 estimated value: $6 million

Peggy Olson, to whom we were first introduced when she was living in Brooklyn with her mother, eventually tires of the commute (and lack of independence?) and decides to move to Manhattan. After a brief stint with a roommate, Peggy and her boyfriend, Abe Drexler, buy a brownstone on the Upper West Side, which was seedy at the time.

Peggy's apprehensive about the move to such a gritty neighborhood, but Abe justifies it. "It's still run-down, so it's sort of cheap. Just get some lumber, a coat of paint. ... People are doing it," he says.

The '60s were a time of transition for the Upper West Side—it was considered a "working class" neighborhood (think "West Side Story," filmed in 1961). Around that time, New York City began an urban renewal initiative, tearing down several blocks of housing projects to build Lincoln Center.

Along with those efforts, property values increased throughout the 1960s. But, the Upper West Side had moderate increases compared with other neighborhoods, Galka said.

When Peggy moved into her brownstone in 1968, the area was still seedy, though far less than it had been eight years earlier. Her brownstone would have gone for about $25,000. For comparison, the same brownstone on the Upper East Side would have been three to four times that price. Today, the home would be worth about $6 million, on a par with its counterparts on the Upper East Side.

Peggy's brownstone AMC

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Pete and Trudy's Upper East Side apartment

Address: East 83rd Street and Park Avenue

1960 estimated value: $35,000

2015 estimated value: $2.5 million

Remember when Pete and Trudy Campbell rented a 1,500-square-foot apartment on the Upper East Side? Yeah, we almost didn't either.

It was home for the smarmy Pete for a couple of seasons while he hustled for partner status at Sterling Cooper, and before the arrival of the couple's only child.

For more than 100 years, the Upper East Side has been considered the premier residential neighborhood in New York City. In 1960, when the Campbells bought their apartment, the film "Breakfast at Tiffany’s" would have just begun filming in the area.

Their apartment is nestled in "a very ritzy, very special area of the city," Serhant said. "It's in the heart of the Upper East Side, in a great school district."

The neighborhood has been home to many of the country’s most prominent families, including the Kennedys, Astors, Rockefellers, and Roosevelts. This fits squarely with Pete's pedigreed family, who are said to have once "owned everything north of 125th Street."

In 1960, a 1,500-square-foot apartment on the Upper East Side would have run about $35,000. Today, the median price is about $2.5 million, Galka said.

Similar apartments currently on the market have asking prices from $900,000 to $4.3 million, with an average of $2.4 million, Galka said.

Pete and Trudy's Upper East Side apartment AMC

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Pete and Trudy's home in Cos Cob, CT

Address: Unspecified

1960s estimated value: $20,000

2015 estimated value: $250,000

By the start of Season 5, Pete and Trudy have moved to a new home in Cos Cob (a village in the wealthy commuter city of Greenwich) in anticipation of the arrival of their baby daughter, Tammy.

The couple describe their new home, located about 30 miles north of New York City, as living "in the country." They host a particularly cringeworthy dinner party so Don and company can see its rustic appeal. And "country" it felt, indeed. So much wood paneling! So many patterns! It was hard to see the house through its loud aesthetics, but we're sure it was charming enough.

According to Census records, an average home in the area would have cost about $20,000 in the 1960s, Galka said. Today, the average home sells for about $250,000.

Pete and Trudy's suburban home AMC

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Pete’s bachelor pad in Manhattan

Address: Unspecified

1966 estimated rent: $100–$150 per month

2015 estimated rent: $4,000 per month

By Season 6, we've watched Pete's hairline recede, his gumption for (ahem) extracurricular activities grow, and Trudy's patience thin. The refined and feisty housewife calls out Pete on his string of affairs (which she apparently knew about all along) and tells him to keep it out of her house and out of their city altogether. Enter: Pete's Manhattan love nest (sort of).

Though the location of Pete’s apartment is never mentioned, a fitting neighborhood would be the East Village, Galka said. At the time it was a dense, trendy, and young area that had just begun to develop its own identity. Previously, it was just the northern part of the Lower East Side. The East Village is considered the birthplace of punk rock, and amps were just starting to be plugged in by aspiring musicians in the area.

Pete's one-bedroom apartment could have been rented for as little as $100 to $150 per month in 1966. Today, his cost would be a whopping $4,000.

"The area would have been a little seedy, but rent was inexpensive," Galka said. "And the location was central and convenient, perfect for stay-overs in the city—particularly for someone with a 'social life' as active as Pete's."

Pete's bachelor pad AMC

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Roger's Upper East Side apartment

Address: 31 East 66th Street, #14A

1960 estimated value: $60,000

2015 estimated value: $5 million–$8 million

It took five seasons before we got a glimpse of Roger Sterling's home, and that was only thanks to a help-me-home note he scribbled before doing LSD. Thanks, acid! But now we know: Roger lives at 31 East 66th Street, #14A. Sadly, like several others in the show, it's a ghost address near Madison Avenue.

In 1960, a three-bedroom apartment in this area of the Upper East Side would have sold for about $60,000, Galka said. Although 31 East 66th Street doesn't exist, the luxury condominium at 40 East 66th Street is a close match. Over the past few years, its three-bedroom apartments have sold for $5 million to $8 million.

Roger Sterling's apartment

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Joan's Greenwich Village apartment

Address: 42 West 12th Street

1960 estimated rent: $200–$300 per month

2015 estimated rent: $4,500–$5,500 per month

Even as a single mother in a nuclear-family-focused era, Joan Holloway is nothing if not classy. So it's fitting that she would choose a home in a historically classy area of New York—the northern section of Greenwich Village, which has been an expensive location as far back as New York’s Victorian days. (In fact, the main character in Edith Wharton’s "The Age of Innocence," Newland Archer, is said to live at 98 West 12th Street.)

In 1960, Joan's apartment (about five blocks north of Don's bachelor pad) would have rented for about $200 to $300 per month. Today, a similar apartment in Greenwich Village would cost between $4,500 and $5,500 per month.

Joan's apartment AMC

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Anna’s home in Long Beach, CA

Address: 4021 S Carolina Street, San Pedro, CA

1960s estimated value: $15,000

2015 estimated value: $600,000

The Long Beach home that Don bought for Anna was filmed at a real Los Angeles–area address, Galka said: 4021 S Carolina St. In the early 1960s the home would have sold for about $15,000. Today, the value is roughly $600,000.

Anna Draper's house AMC

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Megan’s California bungalow

Address: Unspecified in Laurel Canyon, CA

1960s estimated value: $15,000–$20,000

2015 estimated value: $500,000–$800,000

With its wood paneling and bold colors and patterns, Megan’s Laurel Canyon bungalow highlights the bohemian movement of the late 1960s in all its glory. Back then, Laurel Canyon was ground zero for rock 'n' roll (think Jim Morrison and Crosby, Stills & Nash).

The hippie hideaway would have fetched between $15,000 and $20,000 in the 1960s, Galka said. Today, comparable homes with views of the valley sell for between $500,000 and $800,000.

Megan's bungalow AMC

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Did we leave something out of our (mostly) comprehensive guide? Let us know in the comments.

Have a tip? A home worth talking about? Hit us up at news@realtor.com