Google Earth and time travel

Pick a date.  Now pick a state. Pick a date and a state and I will show you the state and county boundaries on that exact date using Google Earth.   I know you’ve heard of Google Earth and have probably used it.  You may have heard of the Atlas of Historical County Boundaries (AHCB) and, if so, have probably used it.  Have you used them both TOGETHER?  Until today I didn’t know it was possible.  Very cool!