terra incognita

The logician Kurt Gödel proved the existence of such mathematical terra incognita nearly a century ago.

Although many thousands know well the district of the Broads, yet to the bulk of people it is still a terra incognita.

Such theories were possible only when the whole of totemic culture was as yet a terra incognita.

The materials of which they were composed were mostly terra incognita to us, but some of them tasted very nice.

This terra incognita, at the period of which we speak, was El Dorado to the European imagination.

Until very recently, Mexico was properly described as Terra Incognita.