The green mountains cannot block it - after all, it flows east; history will not reverse.
Tips
history
From Xin Qiji 辛弃疾's 《菩萨蛮·书江西造口壁》 (Southern Song): '青山遮不住,毕竟东流去。' (The green mountains cannot block it; after all, it flows east.) Most Chinese rivers run east, so 'flowing east' in classical verse evokes unstoppable forward movement.
usage
Always paired with 青山遮不住. 毕竟 (classical) = in the end, after all.