The United States is a young country founded on complicated ideals-ones that it still strives to fulfill. Many of those ideals were established in the 1776 Declaration of Independence-when colonists decided to separate from Great Britain. Learn about the impact of the declaration on the history of the United States. Events that Changed Your World When we get sick, our doctors give us medicine. When we want to visit our grandparents across the country, we hop on a plane. And when we want something in our community to change, we vote for people who share our ideas. A lot of the things we have and do now began as strange or challenging ideas-or even accidents! Discover the history behind events that changed your world-and the people who made them possible.