On this day in 1819, about 60,000 people gathered in St. Peter’s Field in Manchester to demand parliamentary reform. They were met by the 15th Hussars, who charged into the crowd with swinging sabres. At least 18 protesters were killed and several hundred received awful injuries.
The immediate effect was to cause the Government to pass the Six Acts, repressing further demonstrations. But the massacre and the repression eventually gave way to the Reform Act of 1832.
It is to martyrs such as those that suffered at Peterloo that we owe our freedoms, such as they are, today.
Jak's View of Vancouver v.3 
Where is this Peterloo, Manchester
Looked it up: Manchester, Lancashire, England