I have heard the theory that it evolved this way for higher UV protection that was not needed in underwater organisms. Curious if it was really that much of a competitive advantage though.

Edit: okay more recent studies show not so much protection but basically filtering and redirecting light so out eyes can see better color on land. See this comment: https://lemmy.world/comment/18892927

Came here to make sure this was here

Or the US rail system that used exploited labor to build it out.

[Redacted security question answer]