I'm notoriously bad about dates, so I did not mind paying $19.95 for this computer app from the Apple Store. Here's the full description of what it does:
And here's how I used it. I started by filling in the important dates during and leading up to the Civil War. Then I added my characters actions, so that their dates made sense of what was going on in the world around them. Here's just one section of the resulting chart:
You can vary all sorts of things, like the colors. Dates adjust to the number of events you enter. When I started this particular timeline, the year hatches were only about a quarter of an inch apart. You can also print out the events on a spreadsheet that transfers seamlessly to Excel. This gave me a chart of exactly the details I needed to keep tract of.
As the list above points out, you can add pictures, videos, maps, etc. to any event, but I haven't needed to do that.