diff --git a/libbettola/include/bettola/game/chunk.h b/libbettola/include/bettola/game/chunk.h
index 6778aca..2b66dfb 100644
--- a/libbettola/include/bettola/game/chunk.h
+++ b/libbettola/include/bettola/game/chunk.h
@@ -8,10 +8,14 @@ namespace Game {
 const int CHUNK_WIDTH   = 32;
 const int CHUNK_HEIGHT  = 32;
 
+const int CHUNK_BORDER_SIZE = 1;
+const int CHUNK_DATA_WIDTH  = CHUNK_WIDTH   + CHUNK_BORDER_SIZE * 2;
+const int CHUNK_DATA_HEIGHT = CHUNK_HEIGHT  + CHUNK_BORDER_SIZE * 2;
+
 struct Chunk {
   std::vector<float> heightmap;
 
-  Chunk(void) : heightmap(CHUNK_WIDTH * CHUNK_HEIGHT) {}
+  Chunk(void) : heightmap(CHUNK_DATA_WIDTH * CHUNK_DATA_HEIGHT) {}
 };
 
 } /* namespace Game. */
diff --git a/libbettola/include/bettola/game/terrain.h b/libbettola/include/bettola/game/terrain.h
index eeb2e55..9e57b45 100644
--- a/libbettola/include/bettola/game/terrain.h
+++ b/libbettola/include/bettola/game/terrain.h
@@ -21,7 +21,10 @@ inline float get_height_at(const BettolaLib::Game::Chunk& chunk, float local_x,
   if(local_x < 0 || local_x > max_coord || local_z < 0 || local_z > max_coord) {
     int x = std::max(0, std::min((int)local_x, CHUNK_WIDTH  - 1));
     int z = std::max(0, std::min((int)local_z, CHUNK_HEIGHT - 1));
-    return chunk.heightmap[z*CHUNK_WIDTH+x] * 5.0f; /* Apply height scaling. */
+    /* Adjust index for border. */
+    int data_x = x + CHUNK_BORDER_SIZE;
+    int data_z = z + CHUNK_BORDER_SIZE;
+    return chunk.heightmap[data_z*CHUNK_DATA_WIDTH+data_x] * 5.0f; /* Apply height scaling. */
   }
 
   /* Get integer and fracctional parts of the coords. */
@@ -31,10 +34,14 @@ inline float get_height_at(const BettolaLib::Game::Chunk& chunk, float local_x,
   float z_frac = local_z - z_int;
 
   /* Get heights of the four corners of the grid cell. */
-  float h00 = chunk.heightmap[z_int     * CHUNK_WIDTH+x_int];
-  float h10 = chunk.heightmap[z_int     * CHUNK_WIDTH+(x_int+1)];
-  float h01 = chunk.heightmap[(z_int+1) * CHUNK_WIDTH+x_int];
-  float h11 = chunk.heightmap[(z_int+1) * CHUNK_WIDTH+(x_int+1)];
+  /* Adjust indices for bordder. */
+  int x0 = x_int + CHUNK_BORDER_SIZE;
+  int z0 = z_int + CHUNK_BORDER_SIZE;
+
+  float h00 = chunk.heightmap[z0     * CHUNK_DATA_WIDTH + x0];
+  float h10 = chunk.heightmap[z0     * CHUNK_DATA_WIDTH + (x0+1)];
+  float h01 = chunk.heightmap[(z0+1) * CHUNK_DATA_WIDTH + x0];
+  float h11 = chunk.heightmap[(z0+1) * CHUNK_DATA_WIDTH + (x0+1)];
 
   /* Bilinear interpolation. */
   float h_x0 = h00    * (1 - x_frac) + h10  * x_frac;
diff --git a/libbettola/include/bettola/network/chunk_message.h b/libbettola/include/bettola/network/chunk_message.h
index ddd832d..d367ae5 100644
--- a/libbettola/include/bettola/network/chunk_message.h
+++ b/libbettola/include/bettola/network/chunk_message.h
@@ -7,7 +7,7 @@ namespace Network {
 struct ChunkMessage {
   int chunk_x;
   int chunk_z;
-  float heightmap[BettolaLib::Game::CHUNK_WIDTH * BettolaLib::Game::CHUNK_HEIGHT];
+  float heightmap[Game::CHUNK_DATA_WIDTH*Game::CHUNK_DATA_HEIGHT];
 };
 
 } /* namespace Network. */
diff --git a/src/graphics/chunk_mesh.cpp b/src/graphics/chunk_mesh.cpp
index 07c62bd..fc4d017 100644
--- a/src/graphics/chunk_mesh.cpp
+++ b/src/graphics/chunk_mesh.cpp
@@ -10,8 +10,13 @@ ChunkMesh::ChunkMesh(int chunk_x, int chunk_z, const BettolaLib::Game::Chunk& ch
   for(int z = 0; z < BettolaLib::Game::CHUNK_HEIGHT; ++z) {
     for(int x = 0; x < BettolaLib::Game::CHUNK_WIDTH; ++x) {
       /* Vertex position. */
+      /* Index into the full 34x34 data array, offsetting by the border size. */
+      int data_x = x + BettolaLib::Game::CHUNK_BORDER_SIZE;
+      int data_z = z + BettolaLib::Game::CHUNK_BORDER_SIZE;
+
       _vertices.push_back((float)(chunk_x * (BettolaLib::Game::CHUNK_WIDTH-1) + x));
-      _vertices.push_back(chunk.heightmap[z * BettolaLib::Game::CHUNK_WIDTH+x] * 5.0f); /* 5x scale height */
+      /* 5x scale height */
+      _vertices.push_back(chunk.heightmap[data_z * BettolaLib::Game::CHUNK_DATA_WIDTH+data_x]*5.0f);
       _vertices.push_back((float)(chunk_z * (BettolaLib::Game::CHUNK_HEIGHT-1) + z));
 
       /* Vertex normal. */
@@ -47,12 +52,15 @@ ChunkMesh::ChunkMesh(int chunk_x, int chunk_z, const BettolaLib::Game::Chunk& ch
 
 BettolaMath::Vec3 ChunkMesh::_calculate_normal(int x, int z, const BettolaLib::Game::Chunk& chunk) {
   /* Get heights of adjacent certices. */
-  float height_l = chunk.heightmap[z*BettolaLib::Game::CHUNK_WIDTH+(x>0?x-1 : x)] * 5.0f;
-  float height_r = chunk.heightmap[z*BettolaLib::Game::CHUNK_WIDTH+
-    (x<BettolaLib::Game::CHUNK_WIDTH-1?x+1 : x)]*5.0f;
-  float height_d = chunk.heightmap[(z>0?z-1 : z)*BettolaLib::Game::CHUNK_WIDTH+x]*5.0f;
-  float height_u = chunk.heightmap[(z<BettolaLib::Game::CHUNK_HEIGHT-1?z+1 : z)
-                                    * BettolaLib::Game::CHUNK_WIDTH+x]*5.0f;
+  /* Index into the full 34x34 data array, offsetting by the border size. */
+  int data_x = x + BettolaLib::Game::CHUNK_BORDER_SIZE;
+  int data_z = z + BettolaLib::Game::CHUNK_BORDER_SIZE;
+
+  /* Thanks for the border.. We can sample adjacent vertices without boundary checks now. */
+  float height_l = chunk.heightmap[data_z*BettolaLib::Game::CHUNK_DATA_WIDTH+(data_x-1)] * 5.0f;
+  float height_r = chunk.heightmap[data_z*BettolaLib::Game::CHUNK_DATA_WIDTH+(data_x+1)] * 5.0f;
+  float height_d = chunk.heightmap[(data_z-1)*BettolaLib::Game::CHUNK_DATA_WIDTH+data_x] * 5.0f;
+  float height_u = chunk.heightmap[(data_z+1)*BettolaLib::Game::CHUNK_DATA_WIDTH+data_x] * 5.0f;
 
   BettolaMath::Vec3 normal = { height_l - height_r, 2.0f, height_d - height_u };
 
diff --git a/srv/game/world.cpp b/srv/game/world.cpp
index 3169788..bfb8256 100644
--- a/srv/game/world.cpp
+++ b/srv/game/world.cpp
@@ -21,14 +21,16 @@ BettolaLib::Game::Chunk& World::get_chunk(int x, int z) {
 }
 
 void World::_generate_chunk(BettolaLib::Game::Chunk& chunk, int chunk_x, int chunk_z) {
-  for(int z = 0; z < BettolaLib::Game::CHUNK_HEIGHT; ++z) {
-    for(int x = 0; x < BettolaLib::Game::CHUNK_WIDTH; ++x) {
+  for(int z = 0; z < BettolaLib::Game::CHUNK_DATA_HEIGHT; ++z) {
+    for(int x = 0; x < BettolaLib::Game::CHUNK_DATA_WIDTH; ++x) {
       /* Calculate world coordinates. */
-      float world_x = (float)(chunk_x * (BettolaLib::Game::CHUNK_WIDTH  - 1) + x);
-      float world_z = (float)(chunk_z * (BettolaLib::Game::CHUNK_HEIGHT - 1) + z);
+      float world_x = (float)(chunk_x * (BettolaLib::Game::CHUNK_WIDTH  - 1)
+        + (x - BettolaLib::Game::CHUNK_BORDER_SIZE));
+      float world_z = (float)(chunk_z * (BettolaLib::Game::CHUNK_HEIGHT - 1)
+        + (z + BettolaLib::Game::CHUNK_BORDER_SIZE));
 
       /* generate noise value. */
-      chunk.heightmap[z * BettolaLib::Game::CHUNK_WIDTH + x] = m_noise.GetNoise(world_x, world_z);
+      chunk.heightmap[z * BettolaLib::Game::CHUNK_DATA_WIDTH + x] = m_noise.GetNoise(world_x, world_z);
     }
   }
 }