On December 6, 1928, in the town of Cienaga, Colombia, thousands of families gathered in the town square for Sunday Mass. Most of the men in the area had been on strike against the banana plantations for nearly a month. They were demanding written contracts, six-day weeks, and to get paid in cash rather than company script.
The Columbian government responded by sending out the army, which set up machine guns on the roofs and at the corners of the square. After giving a five minute warning, the troops opened fire despite a lack of any provocation from the strikers.

Banana strike leaders