Which are the most used holes/sewers to make defense in PvP, that can be blocked stacking over them?

Question

I know for example the one west of the post Office in ab'dendriel.

Which ones are also used to make traps for defense?

Answer 1

There are few places used to make defense on Pvp Worlds:

Port Hope Blessings located here

Hidden shovel hole (Treasure Hunt Quest) in Port Hope located here and here

Yalahar Cemetery Quarter here and here

Zao Steppe here 

Zao Muggy Plains here