In August, the United States ended the Intermediate Range Nuclear Forces Treaty Land mark the landmark agreement in 1987 with the former Soviet Union band, ground based nuclear ballistic and cruise missiles with ranges of 500 to 5000 kilometers.

The United States and NATO allies said Russia had violated the agreement a long time ago.

In this example, Landmark describes a very important event or achievement.

A landmark is an object or structure on land that is easy to see and recognize.