One thing it's very hard to miss when you arrive in Auckland is the newest volcano on the block, Rangitoto:

Only 600 years old, the name derives from the Maori phrase
Te Rangi totongia a Tamatekapua, meaning `the day the blood of Tamatekapua was shed'. Tamatekapua was the chief of one of the first Maori canoes to arrive on New Zealand with Polynesian settlers. Apparantely they thought his death more violent than perhaps it was...
Anyway, ever since we'd arrived, I'd been itching to climb it, so last Sunday we headed out on an early morning ferry. Although from afar the island appears to be covered in quite heavy woodland, being such a new bit of land, there are lots of areas of bare lava field, and apparently the forest is only about 200 years old.

The hike to the top took less than an hour; on the way we got to explore some lava caves - nothing too claustrophobic but you definitely needed to take a torch.
The views from the top were amazing, both back towards the city:

and out the other way into the bay: