diff --git a/core/src/com/unciv/ui/worldscreen/unit/UnitActions.kt b/core/src/com/unciv/ui/worldscreen/unit/UnitActions.kt
index 2c3920e193..2dbb3fb73f 100644
--- a/core/src/com/unciv/ui/worldscreen/unit/UnitActions.kt
+++ b/core/src/com/unciv/ui/worldscreen/unit/UnitActions.kt
@@ -87,7 +87,7 @@ object UnitActions {
 
         val improvement = tile.getTileResource().improvement
 
-        if (tile.improvement == null
+        if (tile.improvement == null && tile.ruleset.tileImprovements.containsKey(improvement)
                 && unit.civInfo.tech.isResearched(tile.ruleset.tileImprovements[improvement]!!.techRequired!!))
             return UnitAction(UnitActionType.Create, "Create [$improvement]",
                     action = {