|This article is about an older version of DF.
A ruin is a former settlement that has been destroyed in a war, rampage, or other reasons.
Prior to version 0.27.173.38a, ancient ruins were randomly placed hidden sites, much like caves, that contained various structures inhabited by undead humans. Generating a world in an older version and then upgrading it will result in these ancient ruins being completely empty if visited for the first time, though previously-visited ruins should still exist.
A dwarven ruin is an empty mountainhome. Appears same as populated one, minus dwarves. [Verify]
Human ruins will be as generated, but parts of buildings' floors and walls will be replaced with furrowed sand/dirt.
Elven ruins will appear on the map, but they are otherwise indistinguishable from the surrounding wilderness.