You can refer to an important stage in the development of something as a landmark. a landmark arms control treaty The baby was one of the big landmarks in our relationship
A specific location or identifiable natural or man-made geographic feature Also referred to as a waypoint in G P S navigation
Any object which is fixed to the ground and may serve as a guidepost for a survey or boundary Also known as "monument"
A landmark is a building or feature which is easily noticed and can be used to judge your position or the position of other buildings or features. The Ambassador Hotel is a Los Angeles landmark
an event marking a unique or important historical change of course or one on which important developments depend; "the agreement was a watershed in the history of both nations"
A conspicious object, natural or man-made, located near or on land, which aids in fixing the position of an observer
Monument of material mark or fixed object used to designate a land boundary on the ground: any prominent object on land that may be used to determine a location or a direction in navigation or surveying