Answer: I believe it is the taking of Richmond that took the longest and was the hardest.
Explanation: Many soldiers on both sides lost their lives over four years of campaigning.
The causes of mudslides normally refer to large amounts of water cause dirt on a slope to fall, and while they're <em>involved</em> with erosions, the difference is mudslides typically refer strictly to water, meanwhile erosions refer to wind, water, or other natural agents.
Hope this helps. I apologize if it doesn't.
