The Alamo, the place where American liberty defenders stood against the marauding hoards of Mexicans, galvanizing the American troops to fight for liberty and freedom! To the Mexicans however it is the place where American Terrorists made their first stand, were decimated but sparked the American Invasion. Both stories are mostly true (one more so *CoughcoghMexico'scoughcough*) and both are biased so lets take a non biased view of it.
IT started with Mexico opening it's borders to the American settlers, which is awesome. The settlers did their thing and lived in Mexico for a while, eventually the there were too many migrants in Mexico (sounds familiar except if we just let the in our problems would be solved so lets just let them in) so they had to close their borders. Americans did not like that and felt their liberty was being infringed and started a revolution and the first true battle was at the Alamo. Simple summaries for the win! Peace!