1836
Battle of the Alamo
The setting
San Antonio de Bexar, Texas
Fortified former mission compound with low, incomplete walls
Reveal the outcome
Recorded sideRepublic of Texas (Texian and Tejano defenders)
Recorded resultAnnihilated; nearly all defenders killed
Mexican victory; total loss of the Texian garrison
How the atlas explains it
This was a doomed last stand, not a win: heavily outnumbered defenders behind weak walls, with no relief coming, were overwhelmed in a pre-dawn assault and killed almost to a man. Its 'success' was purely moral and temporal, tying down Santa Anna's army for nearly two weeks.
What followed
The massacre, honestly a decisive Texian defeat, became the rallying cry 'Remember the Alamo!' that galvanized recruitment and hardened resolve for the campaign that ended at San Jacinto.