Everybody has heard of the big museum in Paris where there is more art than you can possibly view in a week. There are other good reasons to visit the Louvre if there isn't time or desire for long queues and endless rooms with art.
The Louvre is the oldest art museum in Paris and was officially opened in 1750. The buildings are much older and the original castle is over 800 years old. Over the years the palace has been rebuilt and added to. The palace as we know it today was completed in 1876. The famous glass pyramid was officially opened in 1989.
To walk through the Louvre and see the buildings from the outside is impressive. Sculptures and ornaments covers walls, windows, doors and roofs. There is a lot to explore for the eye and the Louvre is certainly an architectonic masterpiece worth visiting.
Under the museum is a mall and exhibitions. This is where you will find the displays for contemporary art, photography and so on. The shops are expensive and clearly aimed at the tourists, but it's worth exploring the world under the museum. This is where you will find the original fortress walls of the castle, many feet under the surface.
After the visit at the palace it's logic to wander through the Jardin des Tuileries towards the Place de la Concorde which is the beginning of the Champs-Élysées. Louvre is the eastern most part of the Voie Triomphale (Way of Triumph) which goes west and currently ends at the New Arch of Triumph about 8 km away.
Metro: line 1 and 7, Palais Royal Musée du Louvre