Architectural Digest presents 50 of the most iconic buildings you must see before you die. This rundown features the coolest, most beautiful, and most famous buildings in the world like Taj Mahal, the Louvre and Eiffel Tower in Paris, NYC's World Trade Center, Gateway Arch in St. Louis, London's Westminster Abbey, Rome's Colosseum and Pantheon, White House in D.C., Sydney Opera House in Australia, Seattle's Space Needle, Leaning Tower of Pisa, and Sistine Chapel in Vatican City.