Ruins Long Forgotten

We have discovered clear signs that … was once densely populated. However, whatever destroyed their civilization did a very thorough job of it: very few useful remains have been found. Our scanners have detected several large cavities deep below the surface that may once have supported life. Perhaps we will have more luck there.

The command below will trigger the "Ruins Long Forgotten" event in Stellaris:

When this event fires, you can choose between the following option:

• Interesting.