diff --git a/android/assets/jsons/Buildings.json b/android/assets/jsons/Buildings.json
index 1a4d0f3c13..f9b68e5419 100644
--- a/android/assets/jsons/Buildings.json
+++ b/android/assets/jsons/Buildings.json
@@ -360,7 +360,7 @@
 		hurryCostModifier:25,
 		percentStatBonus:{science:50},
 		requiredBuilding:"Library",
-		uniques:[] //todo: "City must be bordering a mountain", 
+		uniques:["Must be next to mountain"],
 		requiredTech:"Astronomy"
 	},
 	{
diff --git a/core/src/com/unciv/models/gamebasics/Building.kt b/core/src/com/unciv/models/gamebasics/Building.kt
index e5cbb07d8a..c66978af38 100644
--- a/core/src/com/unciv/models/gamebasics/Building.kt
+++ b/core/src/com/unciv/models/gamebasics/Building.kt
@@ -186,6 +186,9 @@ class Building : NamedStats(), IConstruction{
         if ("Must be next to desert" in uniques
                 && !construction.cityInfo.getCenterTile().getTilesInDistance(1).any { it.baseTerrain == "Desert" })
             return false
+        if ("Must be next to mountain" in uniques
+                && !construction.cityInfo.getCenterTile().getTilesInDistance(1).any { it.baseTerrain == "Mountain" })
+            return false
         if("Can only be built in coastal cities" in uniques
                 && construction.cityInfo.getCenterTile().neighbors.none { it.baseTerrain=="Coast" })
             return false