The "American dream" has powered the hopes and aspirations of Americans for generations. It began as a plain but revolutionary notion: each person has the right to pursue happiness, and the freedom to strive for a better life through hard work and fair ambition. But over time, this dream has come to represent a set of expectations about owning things and making money. So what exactly is the American dream? How did we come to define it? And is it changing?

The American dream has roots in the nation's loftiest ideals - the right to liberty and the pursuit of happiness. So when did it also come to mean a house, a car and a college education?

There are many facets to the American dream, including a strong belief in freedom, and a powerful desire to consume.

An historian first coined the phrase "American dream" in 1931. He said it meant more than having "motor cars and high wages." But for many Americans, that's exactly what it was.

The seeds for America's consumer expectations were planted during a time of widespread scarcity: the Great Depression.

Imagine being told you could buy a house with no money down or attend college for free. That's what the G.I. Bill offered World War II veterans.

The U.S. government unlocked the American dream for millions of veterans in the 1950s – but not for all. Black veterans often got shut out.

The postwar era seemed to promise each new generation more prosperity than the last. The 1970s broke that promise with a long and withering period of inflation.

Each generation is shaped by the economic circumstances of its time. A new generation learned that debt could be smart.

Since Colonial times Wall Street was the province of an elite few. That changed in the 1980s. Millions of Americans hitched their dreams to the stock market.

America's economic tide rose in the 1980s, but more of the nation's wealth flowed to those who were already well-off.

In the 1990s, middle class Americans learned that wealth is in the home.

The American dream is a rallying cry during hard times. But is the dream in crisis?