The FBI is investigating a white South Carolina couple for racial discrimination after they set a cross on fire in their yard facing toward their Black neighbors’ home.
In Scotland, the fiery cross, known as the crann tara, was used as a declaration of war. The sight of it commanded all clan members to rally to the defence of the area. On other occasions, a small burning cross would be carried from town to town. It was used in the War of 1812 between Britain and the U.S. as a means of mobilizing the Scottish Fencibles and militia which were settled in Glengarry County, Ontario against the invaders.
Apparently the KKK were inspired by the Scots
https://en.m.wikipedia.org/wiki/Cross_burning