A fledgling Auckland was not only built on volcanoes but created from them - through the hard graft of Maori stonemasons, prison inmates and a royal elephant named Tom.
Tom, a three-year-old Indian elephant, had been gifted to Prince Alfred, the son of Queen Victoria, on his way to Auckland in 1870. On board on the ship Galatea, Tom carried coal and hauled on ropes with "the strength of 20 men".
During the Prince's month-long visit, Tom stayed in the grounds of the Albert Barracks - penned in by the 3.6m walls of bluestone basalt rock, built by Maori stonemasons and builders and quarried from the volcanic cone of Mt Eden. Until that year, the wall encircled 900 British troops defending Auckland from a possible Maori attack; the following year, it was demolished (only a remnant of the wall stands today on University of Auckland grounds).
Tom the elephant was also put to work during his stay, dragging loads of basalt to the top of Mt Eden (Maungawhau) to help build the trig platform, which still serves as the highest natural point on Auckland's isthmus, 196m above sea level.
The geographical centre of Auckland's urban area, the trig station was used as the reference point to draw up the city's suburbs.
Tom, a pachyderm with a penchant for a pint, would be rewarded for his hard toil with buns, lollies and a few beers in the city's public houses.
Chunks of Mt Eden's explosive past can now be found all across Auckland. QUARRIES AROUND the sides of the scoria cone provided bluestone basalt, the building blocks for roads and buildings in the new city.
Mt Eden Prison was built entirely by its own inmates, who began quarrying basalt on site in 1883; the dark, forbidding fortress completed 35 years later.
The prisoners then shaped hundreds of thousands of blocks for the city's kerbstones; some still shore up Auckland's pavements.
In 1915, stone crushing was listed as the principal industry of Mt Eden Prison " the "Convict Establishment of New Zealand".
Rangitoto rubble was shipped to the city to create some of the first permanent buildings, like the Melanesian Mission House at Mission Bay.
Scoria mined from Mt Wellington lined Auckland's early roads.
Auckland's oldest surviving house, Hulme Court, was built in Parnell in 1843 from bluestone basalt.
The original home of Sir Frederick Whitaker, twice New Zealand's Premier, now houses the New Zealand Olympic Committee.
The noisy, dusty quarries may have helped the colonial settlers form their new city but they also destroyed the volcanoes that Maori had long fought for - coveting them for their rich, fertile soils and ready-made look-outs for fortified pa.
Mt Smart (Rarotonga) is an example of a scoria cone that no longer exists. It was quarried out over a century for Auckland's roads and railways. Volcanoes of Auckland: The Essential Guide says 15 volcanoes in the Auckland Volcanic Field had their cones completely removed by quarrying and another nine were "fiercely ravaged".
Only two of Auckland's cones are left untouched - Rangitoto and Motukorea (Browns Island).
Today all of Auckland's volcanoes are protected from further ruin.
The Volcanic Cones Society continues to fight council and government bodies to keep the enduring volcanoes preserved, right down to protecting views of the cones.
The Auckland Volcanic Field is on the "tentative list" to achieve Unesco World Heritage status by 2020.
The next eruption
Auckland is one of the few cities in the world perched on an active volcanic field; geologists say more eruptions will rock the city one day. That's despite the predictions of Professor Percival - a visiting volcanologist from Switzerland - who was reported in the New Zealand Herald in 1913 as claiming the "nest of volcanoes around Auckland was never likely to become a menace; the whole tendency of volcanic agency was towards a coming end".
The next big blow is unlikely to be from an existing volcano - all vents, except for Rangitoto, have now been naturally blocked. But a new vent could pop out of the volcanic field.
Rest assured, scientists keep a close eye on the city's volatility. An orbiting satellite surveys Auckland with radar every three months to detect if the earth has the slightest new bulge. Over the last seven years, the Devora (Determining the Volcanic Risk for Auckland) project - a collaboration between GNS Science and the Institute of Earth Science and Engineering - has worked on improving assessment of future volcanic hazard.
Sports fans have helped contribute to the science. A special project called BICEP lies under the South Stand at Eden Park, where sensors in a 383m borehole measure movement in the surrounding soil and rock. Not only can it detect deep-seated micro-earthquakes but, during the final of the 2011 Rugby World Cup, it recorded the vibrations of the 60,000 strong crowd celebrating the All Blacks' victorious moments.
Auckland's secret: lava caves
The labyrinth of lava tubes and caves that snakes beneath the feet of oblivious Aucklanders could have concealed 10,000 people had the city come under attack in World War II.
Well, that was the grand plan of the-then Mayor of Mt Eden, R.J. Mills, who back in 1942 suggested the "spacious caves" under his borough could be transformed into wartime shelters. A cave in Shackleton Rd, he declared, could hold 1500 people; another in nearby Marsden Ave could accommodate 1000.
He was prepared to open up more of these ancient volcanic dens should the need for protection arise. Mayor Mills' proposal wasn't as far-fetched as it may sound - Maori once used the caves to hide from enemy tribes; they also laid the bones of their dead to rest in them.
Today Auckland's lava caves - more than 50, and maybe as many as 200 " are hidden away beneath a bustling city, leading a quiet existence in contrast to their volatile beginnings. As molten lava flowed from volcanic vents, it cooled rapidly on the surface, forming a grey basalt crust as a roof. Underneath, the glowing hot lava continued to flow until it ran out, leaving an empty tube.
Many of these cavernous spaces collapsed as the advancing city rolled over them; some were blocked or bulldozed for buildings and roads (a Green Lane cave was filled in to build Ascot Hospital); others crammed with household rubbish. But those that remain are now protected.
Auckland's longest is the 290m-long Wiri Lava Cave, under the Manukau City Centre. With its rare lava stalactites, it was saved from destruction when Wiri Mountain (Matukutururu) was being quarried. After a 25-year battle, the unique cave was declared a scientific reserve in 1998.
The Cave of a Thousand Press-ups, on the eastern side of One Tree Hill's lava field, is a long network of narrow tubes earning its name from its low height - from 20cm to 1.2m.
Stewart's Cave - a booming underground mushroom farm until the 1960s - was formed 28,500 years ago, as lava from the eruption of Three Kings flowed to Western Springs. Groundwater from Mt Eden still soaks through the old lava flows and ends up in the lake at Western Springs Park - one of Auckland's first public water supplies at the end of the 19th century.
Volcanoes by the numbers
Around 50 volcanoes have erupted within 20km of Auckland's centre in the past 250,000 years. Among the earliest eruptions were Pupuke and Onepoto on the North Shore, and the Domain and Albert Park in the city.
Rangitoto was the largest - and most recent - eruption, around 600 years ago. It was the only Auckland eruption witnessed by humans.
The number of years ago the Waitakere Ranges were formed by one of New Zealand's largest-ever eruptions. Waitakere volcano - 50km wide - was centred in the ocean 20km west of Piha and was six times bigger than Ruapehu, Ngauruhoe and Tongariro combined.
The three craters of Maungakiekie (One Tree Hill) helped create one of the largest earth forts in the world. The 18th century home of Waiohua paramount chief Kiwi Tamaki was famed for 1000 hectares of kumara gardens.
Volcanoes help provide Auckland's water supply. More than 2700 cubic metres of fresh rainwater runs through One Tree Hill's lava flows every day; pumps in Onehunga draw off water for the city.