The Johore Battery is a war memorial site in Singapore that dates back to the early 1940s. Some of the other major coastal batteries were the Pasir Laba Battery, Labrador Battery and the Fort Siloso Battery.

As the British were certain that an attack from the Japanese would come from sea, they decided that Britain's naval power should be concentrated along the coast of Singapore to protect the island from any attack from sea.

The British built the Johore Battery in 1939 at the start of World War II, as a gun emplacement site consisting of a labyrinth of tunnels. These tunnels were built to store ammunition to support three 15' inch guns, also known as Monster Guns because of their colossal size. They were the biggest and heaviest coastal artilleries and were able to pierce the armour of battleships. Before Singapore fell into the hands of the Japanese, it is said that orders were sent out to destroy the guns. Tunnels were sealed up after the war.

The Johore Battery remained a secret till April 1991. A replica of the monster gun and 15' inch shell is now located at Johore Battery,  Cosford Road - Changi. A grim reminder of the importance of vigilance at all times and the need to relentlessly review our defence strategies to meet the coming challenges.