The iconic glass pyramid is the main entrance to the Louvre. For a first time visitor, you'll definitely want to see it, and walk around it. If the line is short, you may want to enter this way. However, lines have been known to take up to two hours to get in. Did you know that there are secret entrances into the Louvre? These secret entrances can cut a two hour wait down to a five minute wait.
Pyramide du Louvre: Main entrance
Palais Royal Musee du Louvre: This entrance goes through the mall to the inverted pyramid.
Porte des Lions: As of June 2018, this is opened back up to regular ticket holders.
Passage Richeliue: This is for tour groups only, or those who have annual memberships.
Carrousel: You can re-enter at this location if you already have a ticket, and it's also a quick way to exit. The stairs come up next to the Arc de Triomphe du Carrousel.