7. The Louvre (3 hours) - The Louvre is overwhelming, busy, and hectic. Still, who wants to go to Paris and miss the Mona Lisa? I would make a list of pieces you want to see and map it out before you go. You may consider an organized tour just to keep you focused. You can find info about tours on their official website here. Prior reservations or a Paris Museum Pass are a must, otherwise you will be waiting in line for hours.