milestone
n
1 stone put at the side of a road showing distances in miles 里程碑. 2 (fig 比喻) very important stage or event 重大阶段或事件; 转折点
This victory was a milestone in our country's history. 这一胜利是我国历史的转捩点.
In 1858 an area of poor housing, factories and farm buildings was torn down and Central Park was created, reaching from 59th Street to 110th Street and across three avenues.