diff --git a/data/core/terrain.cfg b/data/core/terrain.cfg
index 3ab9fd91e38..aca3ba2b05c 100644
--- a/data/core/terrain.cfg
+++ b/data/core/terrain.cfg
@@ -1092,7 +1092,6 @@ Most units have about 50% defense in rocky caves, whereas cavalry are limited to
 [/terrain_type]
 
 [terrain_type]
-    symbol_image=void/void
     editor_image=impassable-editor
     id=impassable_overlay
     editor_name= _ "Impassable Overlay"
@@ -1106,7 +1105,6 @@ Most units have about 50% defense in rocky caves, whereas cavalry are limited to
 # wmllint: general spelling unwalkable
 
 [terrain_type]
-    symbol_image=void/void
     editor_image=unwalkable-editor
     id=unwalkable_overlay
     editor_name= _ "Unwalkable Overlay"