‘Wikenigma is a unique wiki-based resource specifically dedicated to documenting fundamental gaps in human knowledge.

Listing scientific and academic questions to which no-one, anywhere, has yet been able to provide a definitive answer [1142 so far].

That’s to say, a compendium of so-called ‘Known Unknowns’….’ ( via Wikenigma )

I’ve been enjoying browsing the site by hitting the ‘random article’ link.