I am pretty sure it is also the most visited museum in the world. Pretty impressive.

You should definitely be able to do two museums in one day. The American History museum had an exhibit on the Presidents the last time we were there. I believe it was to be a permanent exhibit. It was pretty neat. Among the exhibition’s highlights are Thomas Jefferson’s wooden lap desk on which he wrote the Declaration of Independence, the carriage Ulysses S. Grant rode to his second inauguration, the top hat worn by Abraham Lincoln the night of his assassination, George Washington’s battle sword and much more.