Paris is a city that wears its history on its sleeve. Walking its streets feels like walking through time, and at every corner there's another ghost to greet.

Here are a few suggestions if you're looking to stroll through the ages in the City of Light.

Ghost Writer

American expatriates set up camp here after World War I, and no American expat is more immediately identifiable than Ernest Hemingway.

Key West, Fla., may claim him as its own, and Ketchum, Idaho, is where he lies, but Paris is where he came of age.

Even though Harry's New York Bar at 5 Rue Daunou is practically a lampoon of the American pub, it's still a true landmark rich with history.

Opened in 1911 by an expatriate, it's where members of the World War I ambulance corps (as Hemingway was — his eyes are said to have been too bad for the Army) came to render themselves unconscious.

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Like most places like this, Harry's has its grand claims — one is that it's where the White Lady and the Sidecar cocktails were invented and, perhaps a bit more speciously, that it's where the Bloody Mary was born.

Hemingway hung out here early in its existence, but when he returned in the '50s, he found it "overly quaint."

You'll find it to be a welcoming, raucous, saloon-like bar in a town where pat, polite cafés rule the scene.

Harry's was also the name of another Hemingway haunt — this one being at the Hotel Ritz, a place that's not difficult to confuse with the palace at Versailles. In other words, even if you're not hunting for Hemingway's ghost, this hotel is worth the trip just so you can check out a place that you'll never be able to afford.

The Harry's at the Ritz is now called Bar Hemingway, and it's loving tribute to the author, with framed photographs and letters on the walls, first editions of his books on the shelves and cocktails of his invention on the menu.

In Key West, Papa (as he was called by friends and family) waged an experiment in mixology when he placed a glass with two jiggers of water and one jigger of scotch in the freezer.

When he checked it after a few hours, he found the water had frozen, but the scotch had not. When he tipped it back and the scotch cut a refreshing rivulet through the ice, he realized he had made a very important discovery indeed. Bar Hemingway at the Ritz offers this triumph in the drinking sciences.

For the more academically minded, Paris is loaded with other non-ingestible Hemingway attractions, such as Shakespeare and Company — the famous American bookstore and lending library.

This little shop at 37 rue de la Bucherie was at the center of the literary movement in Paris and served as the first publisher to many important works.

If it's pure Hemingway lore you're looking for, the Jardin du Luxemborg is a lovely park where Hemingway claimed to have resorted to pigeon-snatching during what he called his "total poverty period."

As the story goes, he would pose as a bird lover, pushing his son around in his pram while scanning the flock for one with good clarity of eye.

When the guard went on his coffee break, he'd snatch his victim, wring its neck and throw him under the blanket with his baby. That night, his wife would have fresh squab to serve.

For more Hemingway lore, pick up Noel Riley Fitch's "Walks in Hemingway's Paris," a good guide if you're after Papa's ghost.

If you're after another kind of ghost, read on to find more than a few ...

The Empire of Death

You descend almost 80 feet below street level on a winding spiral staircase to a crypt where the bones of over 6 million Parisians are stacked like kindling.

"Halt! This is the Empire of Death" is the epitaph that greets visitors to the Denfert-Rochereau Ossuary, located in a pleasant Left Bank neighborhood near Paris' Montparnasse district.

Other cheeky phrases are etched in Latin throughout, such as "Man, like a flower of the field, flourishes while the breath is in him, and does not remain nor know longer his own place" and "He who despises life doth not fear to die." So much for "Please, no flash photography."

The catacombs of Paris, as the entire underground network is colloquially known, is the result of excessive quarrying of raw materials starting in the 12th century — essentially the Paris that is above ground came from what was below ground.

When a large collapse in 1774 destroyed buildings near Enfert Street, the Inspector General began reinforcing and mapping the labyrinth.

When decomposing bodies from the Cimetiere des Innocents began seeping into the Les Halles (the central market) cellars, bringing swarms of ravenous rats and widespread epidemic, the bodies were disinterred and transplanted to the tunnels. A few blessings from the local clergy later, and the ossuary was born.

It is truly like nothing you've seen before. After the initial descent, there is a short jog through tunnels straight out of any "Dungeons and Dragons" adventure — the kind of place any Harry Potter fan would gleefully explore. Then you get to the bones.

Stone walls give way to ... femoral walls — leg bones stacked like firewood, the knobby ends lined up flush with one another, creating an uneven surface of rough decay.

Imagine 12 million leg bones stacked on top of one another — a Great Wall of human remains — though it gets far more macabre than that.

Embedded in the walls in decorative patterns are skulls — some complete, most sans lower mandible — creating a ghastly mosaic of death. Some skull mosaics are patterned into crosses — maybe 10 vertical and five across; others are fixed in the walls in arch patterns. Some entire walls are topped off with a kind of skull crown molding.

The walls are only about 5 feet high and are maybe three or four layers deep. On top of the neatly stacked leg bones are, well, the rest of the skeletons, just randomly tossed.

Even without just a layman's understanding of anatomy, the average visitor would be able to identify metacarpals, phalanges and rib bones, rib bones, rib bones. The one word that comes to mind is ... mortifying.

And yet, they make for a great tourist attraction. During the high tourist season, go early in the day so you can take them in at your own pace. And bear in mind, they are not for the faint of heart.

Some General Tips for Traveling in Paris

Book now, travel later. Summer is not the time to go anywhere in Europe, and every year it seems to get hotter and hotter over there. Many hotels in the countryside do not have air conditioners, so if you want to actually enjoy your trip, stick to the fall or the spring.

Paris is a city best suited to gray skies, storm clouds and a nip in the air, so I'd recommend October through December for a visit.

Buy euros. Credit cards have made travelers checks obsolete and before the euro, they were the easiest way to get by. But now that their currency isn't counted in the thousands, using euros is just as easy as using dollars in all but one way: The dollar is weaker.

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