In which John Green teaches you about the Mexican-American War in the late 1840s, and the expansion of the United States into the western end of North America. In this episode of Crash Course, US territory finally reaches from the Atlantic coast to the Pacific Ocean. After Oregon was secured from the UK and the southwest was ceded by Mexico, that is. Famous Americans abound in this episode, including James K Polk (Young Hickory, Napoleon of the Stump), Martin Van Buren, Zachary Taylor, and Winfield Scott. You'll also learn about the California Gold Rush of 1848, and California's admission as a state, which necessitated the Compromise of 1850. Once more slavery is a crucial issue. Something is going to have to be done about slavery, I think. Maybe it will come to a head next week.