Big river : Lewis and Clark descend the Columbia (1805)
No water : Jedediah Smith crosses the desert (1826)
Independence Day : Narcissa and Eliza cross the Rockies (1836)
I have found it! : James Marshall discovers gold (1848)
Blood on the trail : the Grattan fight (1854)
They're off! : first ride of the Pony Express (1860)
A railroad to the moon : completion of the transcontinental railroad (1869)
We shoot, we ride fast, we shoot again : the Battle of the Little Bighorn (1876)
Throw up your hands! : showdown in Tombstone (1881)
Gold! gold! gold! : the Klondike stampede (1897).