The Grand Louvre—a former royal palace opened to the public as an art gallery when the Revolution struck—has 60,000 square meters of galleries displaying more than 30,000 works spanning three millennia, all of it seen by 8.5 million people each year, making it the world's most visited museum.
In other words: It's big.
Besides one of the world's top painting galleries, the Louvre also houses a remarkable collection of antiquities from Greece, Etruria, Rome, Egypt, and the Orient; a sculpture section that boasts two of Michelangelo's Slaves; and a fine decorative arts division.
It would take about three days to scratch properly the surface of all seven departments of the Louvre.
Heck, it takes at least half a day merely to walk through the halls to see just the three most famous of many instantly recognizable artistic icons that call the Louvre home:
The floor plans and information desks on site will help you get a handle on the basic layout and plan your visit, but here's one tip. The Louvre's problem is that there are too many masterpieces.
If you have the time, try to take in the Louvre over several visits. In the long run, it's worth the multiple admissions (though you needn't pay over and over if you use the highly recommended Paris Museum Pass).
To avoid aesthetic overload, and since you can only absorb so much, on a first visit you will probably have to pretty much ignore most of the works you're passing—pieces that might have been the pride of a lesser museum—in order to devote your art appreciation energies to the most signficant works on display.
The short shortlist of other Louvre highlights include:
Honestly? I'd budget a full day for the Louvre. Heck, I'd return for two days (though not back-to-back).
The Louvre ranks high on the short list of the top museums in the entire world—arguably, it could be placed at the top spot.
Still, on a super-tight schedule, you could get away with spending just 3–4 hours in the Louvre.
If your interest lies more in having checked the Mona Lisa off your sightseeing list than in actually spending time admiring all the other art—and it kills me to say this—but you could rush through in just 45–60 minutes (but do try and give the art a chance, OK?).
Avoid the line snaking from the glass pyramid entrance and head instead to the Louvre's western entrances at Carrousel (in the open courtyard) and Porte des Lions (in the southern wing; closed Fridays).
The Louvre stays open for extened hours Wednesday and Friday nights. Rather than closing at the usual 6pm, it closes at 9:45pm.
Note that, no matter what time the museum itself closes, they start closing the outer galleries 30 minutes early, effectively herding visitors toward the central part of the museum to exit.
Luckily, the main entrance area under the pyramids stays open until 10pm daily (so you can stay in the galleries until the utter last minute and still have plenty of time to browse the gift shop).
Admission to the Louvre is free—and the museum is intensely crowded—on the first Sunday of every month.
La Gioconda (a.k.a. The Mona Lisa) painted by Leonardo da Vinci in 1503–06.