moat; fosse; trench; underground air-raid shelter; dugout
air-raid shelter; bomb shelter
bunker; covered trench; dugout
moat; fosse; canal; ditch
bomb shelter; dugout; trench
water jump (on a racetrack, etc.); moat (around a castle, etc.)
remains of a dugout (usu. military)
inner moat; moat within the castle walls