It was 10 October 1465 – the day of the hotly anticipated wedding of King Alfonso II of Naples. He was set to marry the sophisticated Ippolita Maria Sforza, a noblewoman from Milan, in a lavish ceremony. As she entered the city, the crowds gasped. Before them was a sight so strange and beautiful, it was like nothing they had ever seen before.
Alas, they weren’t staring at the bride to be – they were looking up at the sky. Though it was the middle of the day, the Sun had turned a deep azure, plunging the city into eerie darkness. Rumours began to spread – was it a solar eclipse? As the early dusk lingered on, others suggested it could be a consequence of the weather. After all, they’d had a particularly wet autumn and some claimed they had seen a thick, humid fog rise up into the sky.
This was just the beginning. In the months that followed, European weather went haywire. In Germany, it rained so heavily that corpses surfaced in cemeteries. In the town of Thorn, Poland, the inhabitants took to travelling the streets by boat. In the unrelenting rain, the castle cellars of Teutonic knights were flooded and whole villages were swept away.
Four years later, Europe was hit by a mini ice age. Fish froze in their ponds. Trees failed to blossom and grass didn’t grow. In Bologna, Italy, heavy snow forced locals to travel with their horses and carriages along the frozen waterways.
In fact, what Alfonso’s wedding party witnessed may have been more extraordinary than anyone imagined. Many thousands of miles away in the tropics, a giant volcano was making geological history. This was an eruption so big, it produced an ash cloud which enveloped the Earth and led to the coolest decade for centuries.
The blast itself would have been heard up to 2,000km (1,242 miles) away and created a tsunami which caused devastation hundreds of kilometres away. In terms of scale, it surpassed even the 1815 eruption of Tambora, which unleashed energy equivalent to 2.2 million Little Boy atomic bombs and killed at least 70,000 people. Traces of the eruption have been found from Antarctica to Greenland.
The thing is, scientists can’t find the volcano that did it. What’s going on?
That the ‘unknown eruption’ happened is undisputed – like most mega-eruptions, it vapourised vast quantities of sulphur-rich rock, which was blasted into the atmosphere and eventually snowed down on the poles as sulphuric acid. There it was locked into the ice, forming part of a natural record of geological activity that spans millennia. There’s no other event capable of doing this, short of an asteroid impact.
But establishing its existence is the easy part. What scientists don’t know is – well, pretty much everything else. This is a true geological mystery, one which has left geologists scratching their heads for decades.
It all began with a rumour and a coral-fringed island in the South Pacific. Back in the 1950s, archaeologists visiting Tongoa, Vanuatu heard stories of an ancient landmass which, many generations ago, linked it to the neighbouring island of Epi. It was known as Kuwae – and in the centre was a giant volcano.
Excluding obvious embellishments, such as a local man’s supernatural wrath over being tricked into an incestuous relationship with his mother, the legend boils down to this. One day, after several strong earthquakes, a cataclysmic eruption broke the island in half.