Smithsonian Institution, Washington D.C.
With nineteen museums and galleries, this is the largest research and museum complex in the world. It contains various research stations as well as the National Zoological Park. There are more than 137 million objects detailing America’s history housed at the Smithsonian. The main attractions include Dorothy’s ruby red slippers, the dresses of the first ladies and the Apollo 11 command module at the National Air and Space museum as well as other interesting attractions. There are so many items in the museum that if one spent day and night looking at each of them, they would take about ten years to cover ten percent of the museum.