[4] Known for its sweeping views over the harbour and the Hauraki Gulf, since 1885 the head was mainly used by the military as a coastal defence installation, which left a network of accessible old bunkers and tunnels as its legacy, forming part of the attraction.

The armaments of the fort included 64-pounder Armstrong disappearing guns, searchlights, and a remote-detonated naval minefield across the inner harbour to Bastion Point.

Then during World War II, it became the administrative centre of Auckland's coast defenses, with the regimental headquarters buildings still surviving today.

Also popular are exploratory forays to the gun emplacements and into the tunnel system, which is open to the public to a substantial degree, though torches are needed to explore it.

[citation needed] In the late 1980s and early 1990s there were reports of strange chemical smells and rumours of hidden caverns underneath the hill.

As it was feared that old ammunition was decaying in forgotten parts of the fortifications, a major investigation was started, involving documentary research, geological tests and substantial exploratory digging was done around the hill.

The legislation specified that the land be held in trust "for the common benefit of Ngā Mana Whenua o Tāmaki Makaurau and the other people of Auckland".