Filibuster is a political term today, but in the 1850s it meant a group of men who were either visionary entrepreneurs or no good land pirates - depending on whether you were an American or Mexican.

After more than 80 years of struggle and turmoil, it’s time for Tucson to say farewell to Mexico.

In which we thank the U.S.’s increasingly divisive regional politics and our old friend, Antonio Lopez de Santa Anna, for securing Tucson, Tubac and Tumacácori as part of Arizona.

The international boundary survey commission discovered in 1850 that neither the United States nor Mexico really had a clue about where El Paso was.

It's Round 2 of the struggle to control the vital Colorado River crossing. In one corner we have the reigning champions, the Quechens. Their challenger? The scrappy newcomers, the Americans.

Also, Tucson will finally make peace with its perennial foe, the Apaches ... for like five minutes.

The discovery of gold in California converts Tucson from obscure frontier town to important cross-country stop. Too bad the Americans couldn’t really appreciate it.

Mexico once again puts its trust in Santa Anna, but in the end will find that half the country now belongs to their aggressive north neighbor. The only kicker is no one really knew much about what they had just given away.

War with Mexico has been declared, and with the conflict will come the first real advance of Americans into Arizona, including the longest infantry march in U.S. military history.

In which we bring everyone up to the brink of the Mexican-American War.