Berlin Wall and The Great Wall of China
A relic boundary is a geological feature that represents a former boundary or edge of a rock layer or geologic formation that has since been altered or eroded over time. It provides clues about the past environment and geologic processes that have shaped the area.
Aral Mountains.......divide Europe and Russia
A physical boundary can be a fence, a wall, a river, or a mountain range that separates two areas or properties.
The Pyrenees form the border between Spain and France. As both France and Spain are part of Europe, the Pyrenees do not form a part of Europe's boundary. The Urals or Caucasus mountains from part of Europe's boundary, in the east and in the southeast of Europe.
The Arctic Ocean is the northern boundary of Europe.
The Ural Mountains stretch about 2,500 km from north to south, forming a natural boundary between Europe and Asia. They are considered the conventional boundary marking the separation of the two continents.
Eurasia
Im just going to guess that its a boundary that nature provided, but and example is an ocean, a river, and a mountain.
landscape features
The Caucasus.
Relict boundary is a boundary that has ceased to function, but its imprint can still be detected on the cultural landscape An example would be East and West Berlin.