As the United States advances west, the nature of the land is revealed. What appeared to be a boundless empty terrain was in fact a richly inhabited landscape of diverse indigenous peoples who were not about the surrender without a fight.

Mexican-owned Texas offers land and freedom for those white settlers searching for a fresh start but the influx of 'Americans' would be the catalyst for the brutal Mexican-American War that would change the course of US history forever.

The newly acquired territory of California would prove invaluable as the chance discovery of gold unleashes the largest migration in US history and ignites a vicious debate on slavery, culminating in the American Civil War.

A race for the railroad system to join the east and west coast beings a new chapter in US dominance and leads to the rise of an American icon: the cowboy.

As the century draws to a close, the scars of the systematic ethnic cleansing of native peoples, along with US claims on land stretching the span of the entire continent, seemingly ends the 'frontier' chapter in American history.