Maungauika (North Head)

Maungauika (the Mountain of Uika) is named for one of its original Māori inhabitants of around 800 years ago, and at over 50,000 years old, is one of the oldest cones in the Auckland volcanic field.

In the 1880s during the global "Russian scares," the government rushed to build fortifications on top of and around the maunga, built and maintained largely by prisoners living on a quickly constructed prison at the summit. The site is recognised as New Zealand's most significant coastal defense site. 

Today, you can climb the mountain to visit the decommissioned artillery, including one of the few remaining retractable guns in the world. The biggest draw, though, is being able to freely wander the pitch-black tunnels dug through the volcano by the prisoners over 100 years ago. (Seriously, don't forget a torch!)

If you don't get lost in the tunnels, it's worth sticking around for sunset to see the awesome views over the city, or wandering down to the nearby Torpedo Bay at low tide to explore the volcanic rockpools and see the remnants of an anti-submarine boom.