diff --git a/src/micropolisj/engine/CityEval.java b/src/micropolisj/engine/CityEval.java
index 6c8226d..b22fc6f 100644
--- a/src/micropolisj/engine/CityEval.java
+++ b/src/micropolisj/engine/CityEval.java
@@ -10,6 +10,9 @@ package micropolisj.engine;
 
 import java.util.*;
 
+/**
+ * Contains the code for performing a city evaluation.
+ */
 public class CityEval
 {
 	private final Micropolis engine;
@@ -56,6 +59,9 @@ public class CityEval
 	/** Score for various problems. */
 	public EnumMap<CityProblem,Integer> problemTable = new EnumMap<>(CityProblem.class);
 
+	/**
+	 * Perform an evaluation.
+	 */
 	void cityEvaluation()
 	{
 		if (engine.totalPop != 0) {
diff --git a/src/micropolisj/engine/CityLocation.java b/src/micropolisj/engine/CityLocation.java
index 91faaa6..f5bf824 100644
--- a/src/micropolisj/engine/CityLocation.java
+++ b/src/micropolisj/engine/CityLocation.java
@@ -8,11 +8,24 @@
 
 package micropolisj.engine;
 
+/**
+ * Coordinates of a location (x,y) in the city.
+ */
 public class CityLocation
 {
+	/** The X coordinate of this location.
+	 * Increasing X coordinates correspond to East,
+	 * and decreasing X coordinates correspond to West. */
 	public int x;
+
+	/** The Y coordinate of this location.
+	 * Increasing Y coordinates correspond to South,
+	 * and decreasing Y coordinates correspond to North. */
 	public int y;
 
+	/**
+	 * Constructs and initializes city coordinates.
+	 */
 	public CityLocation(int x, int y)
 	{
 		this.x = x;
diff --git a/src/micropolisj/engine/MapGenerator.java b/src/micropolisj/engine/MapGenerator.java
index 9919380..2173af1 100644
--- a/src/micropolisj/engine/MapGenerator.java
+++ b/src/micropolisj/engine/MapGenerator.java
@@ -12,6 +12,9 @@ import java.util.*;
 
 import static micropolisj.engine.TileConstants.*;
 
+/**
+ * Contains the code for generating a random map terrain.
+ */
 public class MapGenerator
 {
 	Micropolis engine;
@@ -46,6 +49,9 @@ public class MapGenerator
 		return map.length;
 	}
 
+	/**
+	 * Generate a random map terrain.
+	 */
 	public void generateNewCity()
 	{
 		long r = Micropolis.DEFAULT_PRNG.nextLong();