This week, the final four designers travel to Washington D.C. where they visit the Smithsonian Museum to take in the rich history of American fashion. They are challenged with creating a 6 piece collection in one week, but of course there's a twist! They have to present one look early to determine the final three. Then, in another twist, the runway ends in a challenge to create a look in only an hour! And in the end, we say goodbye to a very talented designer in one of the most emotional farewells in Project Runway history.