Structures

Torch Caves

They were removed in V1, before that, they contained a loot chest and were 100 meters away from the birthplace (world center).

Lighthouses

Added in V1, replacing Torch Caves. They will summon blocks every 30 seconds, with a chance to get rocks, wood, iron, gold or a loot chest. The best way to find them is to head in any direction and walk straight until you can't see the birthplace ray anymore. Then turn around and if you see it, run straight for it, in case you don't see it, head in any other direction and try to find it.