Term: Bay View Tragedy
Definition:

Bay View Rolling Mills, late-19th c. (WHi-7015)
Wisconsin's best-known clash between labor and business; when several thousand Milwaukee workers marched toward the Bay View Rolling Mills on May 5, 1886, advocating an 8-hour work day, the state militia opened fire on the unarmed crowd and killed seven people. View more information elsewhere at wisconsinhistory.org
[Source: http://www.wisconsinlaborhistory.org/milestones.html]