And to think this started over Civil War statues (which weren't created until decades afterward during the rise of the Klan and Jim Crow laws but that'snoneofmybusiness). I always thought that particular crowd was against participation trophies for losers...
I don't know the specific dates these statues and other monuments were erected.
The Ku Klux Klan for most of its existence was in the tens of thousands. It reached a membership in the millions only for a brief time, in the early 1920's after World War I, due to:
1) White factory workers had gone of to war in Europe, and were replaced by black labor and immigrants who filled their jobs in factories and worked for lower wages. When the white men came back from the war, factory owners didn't want to give them back their jobs.
2) a huge surge in annual immigration that likewise was displacing and pricing out white workers
The KKK quickly declined in membership because of 1) scandal involving their leadership that swiftly delegitimized them, and 2) a lowering of annual immigration to 200,000-300,000 immigrants a year (that was previous to that over 1 million a year), a policy that lasted until 1965.
