Combining NationMaster.com’s nuanced and annotated time-step images of the evolving United States, an unknown person put together this great animated map. In one click, the drifting lines and changing colors take you through 170 years of history; from late 1789 just after the passing of United States Constitution up to the modern organization which didn’t arise until August 21, 1959, when Hawaii became a state.

It’s particularly interesting watch states such as Georgia or Texas start out as gigantic stretches of land before being slowly whittled away. Or, to see Mexico’s dominance of what is now the southwestern US recede, from its origination in 1821 to its disappearance in 1854.

More from Smithsonian.com:

How the Louisiana Purchase Changed the World

The Cherokees vs. Andrew Jackson

The Law that Ripped America in Two