What famous description did Einstein later give to his addition of the Cosmological Constant?

Answer

His 'biggest blunder'

Einstein later regretted introducing the Cosmological Constant because Hubble's data proved the universe was naturally dynamic, validating the original, unadulterated form of his equations.

What famous description did Einstein later give to his addition of the Cosmological Constant?
HistoryscientistAstronomertheoryPhysicist