This work was part of a set of three posters Swann Galleries sold in 2008 for $4,560, which - grouped together - make a strong graphic impact. The best of the three, meant to attract visitors, may be a luscious flying Lady Liberty carrying the flag with Independence Hall in the background.
The posters of 1926 have a retro rather than deco style, reminding travelers of the Centennial Exposition in 1876, a huge success that launched Americana-collecting as a national pastime.
In November, Swann will be offering a group of Pennsylvania Railroad posters, including a circa 1935 advertisement for the train to Atlantic City, a glamour destination at the time. The design by artist Edward M. Eggleston carries an estimate of $10,000 to $15,000.
But this promotion was not about tourism, Lowry said while filming an episode of Antiques Roadshow on location in Seattle.
The Pennsylvania Railroad was "thinking about filling the seats on their trains. It was not an altruistic campaign - it was a very specific commercial enterprise."
Then there's the Works Progress Administration, an almost entirely philanthropic endeavor during the Great Depression when the U.S. government put hundreds of artists to work highlighting a social agenda that included a "See America" campaign. Philadelphia and Pennsylvania received lots of attention, especially a group of very folksy, stylized travel posters for Pennsylvania Dutch country by artist Katherine Milhous (1894-1977), who went on to become a book illustrator and designer in New York City. She won the Caldecott Medal in 1951 for The Egg Tree.
Because of her position as an important woman artist, collectors put a higher value on her posters. WPA posters in general were created in limited numbers as well, and because they were meant to eventually be taken down and thrown away, there are few examples left, said Lowry.
Perhaps the best advertisement for the city are movie posters: the classic examples, The Philadelphia Story (1940), a copy of which was sold by Heritage Auctions for $3,107 last year, or the 1956 musical remake High Society with local beauty Grace Kelly.
Posters also advertised Philadelphia as an appealing destination for Europeans in the early 20th century - for immigrants and for pleasure travel. In the archives at the Independence Seaport Museum is a poster showing a ship of the German Hamburg America Line bound for the city.
"All up and down the river, there was activity - ships coming in with cargoes and passengers," said chief curator Craig Bruns. "Along the 1300 block of Walnut, you could buy liner tickets at travel agents."
Buyers on a budget can find travel posters from the 1950s and 1960s for less than $1,000. A Mad Men-era Go Greyhound design with a couple feeding pigeons by Independence Hall sold for $570 four years ago.
The accessibility of posters makes them a crowd-pleaser.
"Maybe you were conceived in Pennsylvania or your grandparents lived in Lancaster County," said Lowry. "Whoever you are, whatever you are, wherever you come from - you will find something that resonates."