diff --git a/src/main.rs b/src/main.rs
index c15774e..e28ea87 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -85,26 +85,22 @@ pub fn draw_map(ecs: &World, ctx: &mut Rltk) {
     for (idx, tile) in map.tiles.iter().enumerate() {
         // Render a tile depending upon the tile type, if revealed
         if map.revealed_tiles[idx] {
+            let glyph;
+            let mut fg;
             match tile {
                 TileType::Floor => {
-                    ctx.set(
-                        x,
-                        y,
-                        RGB::from_f32(0.5, 0.5, 0.5),
-                        RGB::from_f32(0., 0., 0.),
-                        rltk::to_cp437('.'),
-                    );
+                    glyph = rltk::to_cp437('.');
+                    fg = RGB::from_f32(0.5, 0.5, 0.5);
                 }
                 TileType::Wall => {
-                    ctx.set(
-                        x,
-                        y,
-                        RGB::from_f32(0.0, 1.0, 0.0),
-                        RGB::from_f32(0., 0., 0.),
-                        rltk::to_cp437('#'),
-                    );
+                    glyph = rltk::to_cp437('#');
+                    fg = RGB::from_f32(0.0, 1.0, 0.0);
                 }
             }
+            if !map.visible_tiles[idx] {
+                fg = fg.to_greyscale()
+            }
+            ctx.set(x, y, fg, RGB::from_f32(0., 0., 0.), glyph);
         }
 
         // Move the coordinates
diff --git a/src/map.rs b/src/map.rs
index 5f92245..75d19d1 100644
--- a/src/map.rs
+++ b/src/map.rs
@@ -14,6 +14,7 @@ pub struct Map {
     pub width: i32,
     pub height: i32,
     pub revealed_tiles: Vec<bool>,
+    pub visible_tiles: Vec<bool>,
 }
 
 impl Map {
@@ -55,6 +56,7 @@ impl Map {
             width: 80,
             height: 50,
             revealed_tiles: vec![false; 80 * 50],
+            visible_tiles: vec![false; 80 * 50],
         };
 
         const MAX_ROOMS: i32 = 30;
@@ -82,18 +84,10 @@ impl Map {
                     let r2_center = map.rooms[map.rooms.len() - 1].center();
                     if rng.range(0, 2) == 1 {
                         map.apply_horizontal_tunnel(r1_center.0, r2_center.0, r1_center.1);
-                        map.apply_vertical_tunnel(
-                            r2_center.0,
-                            r1_center.1,
-                            r2_center.1,
-                        );
+                        map.apply_vertical_tunnel(r2_center.0, r1_center.1, r2_center.1);
                     } else {
                         map.apply_vertical_tunnel(r1_center.0, r1_center.1, r2_center.1);
-                        map.apply_horizontal_tunnel(
-                            r1_center.0,
-                            r2_center.0,
-                            r2_center.1,
-                        );
+                        map.apply_horizontal_tunnel(r1_center.0, r2_center.0, r2_center.1);
                     }
                 }
                 map.rooms.push(new_room);
diff --git a/src/visibility_system.rs b/src/visibility_system.rs
index 47bfc68..8dcfd7e 100644
--- a/src/visibility_system.rs
+++ b/src/visibility_system.rs
@@ -27,10 +27,14 @@ impl<'a> System<'a> for VisibilitySystem {
 
             // If this is the player, reveal what they can see
             let p: Option<&Player> = player.get(ent);
-            if let Some(p) = p {
+            if let Some(_) = p {
+                for t in map.visible_tiles.iter_mut() {
+                    *t = false
+                }
                 for vis in viewshed.visible_tiles.iter() {
                     let idx = map.xy_idx(vis.x, vis.y);
                     map.revealed_tiles[idx] = true;
+                    map.visible_tiles[idx] = true;
                 }
             }
         }