The vast grassland stretches without bound as far as the eye can see.
Tips
usage
Two main registers. (1) Literal - vast space with no edge: 漫无边际 (boundless / rambling). (2) Economic - 边际效用 (marginal utility), 边际成本 (marginal cost). The economics sense is a calque of English 'marginal'.
mistakes
漫无边际 also means 'rambling on without a point' when describing speech or writing - not just literally boundless. 他讲得漫无边际 = 'he talks without coming to the point'.
