There's a lot of beautiful places and things in Paris, and the Louvre is up there on that list. I've been inside 3 times, and the amount of artifacts and pieces is almost unimaginable, I've literally gotten quite lost inside on more than one occasion.
The outside is equally beautiful, the architecture and details are mind boggling; to imagine the construction of such a place is quite a bewilderment.
And of course you have the famous icon of the Louvre, the famous glass pyramid, also notably seen in the film "The Da Vinci Code". It as well is quite a marvel, in it's own modern way.
And if you find yourself in Paris, you may be interested to know that on the first Sunday of every month it's free to go in ! And on every Friday night from 6pm to 9pm I believe, is Youth Night, where they reopen the museum only for youths under 26 years old, for free, from any nationality. But you may want to check with the Louvre website first and see if anything has changed on these offers.