I haven’t been to any of the museums mentioned heretofore, but my two favorites were the Imperial War Museum and Battle of Britain Museum, both located near London.

As far as the Civil War, I think the layout at Vicksburg is superb including the U. S. S. Cincinnati ironclad.

My wife's grandfather had recently been invalided off the ship as Captain of the Afterdeck, while my ggranddad was in the rifle pits alongside the Marine Battery which had participated in the shelling and sinking of her.