Trench

A trench is a long, narrow ditch.

Trench warfare has often been used in defense. Entrenched soldiers can be somewhat safe from enemy fire.  Trench warfare made World War I longer than expected.  The trench coat got its name from there.

Several kinds of trench exist:
 Utility trench has pipes, wires, or other infrastructure
 Road trench carries vehicles
 Military trench provides shelter for soldiers shooting at each other
 Oceanic trench: For example, the Mariana Trench
Rift valley
  Archaeological trench dug by archaeologists
Category:Landforms
Category:War