AdvertisementLandmark At The Louvre: The Pyramid Turns 20December 07, 2009Susan StambergfacebookEmailThe Louvre's famous pyramid turns 20 this year. When architect I.M. Pei first designed it in the 1980s, critics said tampering with the Louvre's majestic architecture was "sacrilegious." But over the years, visitors have warmed up to the giant glass structure. (Sipa via AP Images)