If you want to export builds in Minecraft into files, you could use structure blocks.
It can save builds into files so that you can transfer them between worlds. It does have a size limit of 32 x 32 blocks, but as long as it's not bigger than that, it'll work. Here is a tutorial if you need any help with it:
Do you mean Ruins? They are small stone towers with loot inside. They mostly spawn underwater, but sometimes it can spawn too close to land and appear on land.