The rise of digital cryptocurrency Bitcoin has been spectacular. Defying dire warnings from governments, regulators and central banks the price has accelerated in recent weeks as an ever-growing base of buyers have piled in.
The resulting volatility has been extreme: the price frequently moves by more than 10pc within hours - sometimes less. It is not the only cryptocurrency, but is by far the best known.
The chart below shows how the price of Bitcoin (as measured in US dollars) has changed during the past 12 months.
Investors from all walks of life have caught the bug. The Winklevoss twins Tyler and Cameron, made famous after successfully suing Facebook founder Mark Zuckerberg, are thought to be the first Bitcoin billionaires after buying $11m worth in 2013 – now worth more than $1.6bn.
Speculators of more modest means have also made thousands as the price has climbed by more than 1,500pc since January, smashing through $18,000 in December.
Holders are attracted not only by the potential of making an enormous return in a short space of time, but the challenge the digital currency represents to governments, central and commercial banks.
This latter group appear to have abandoned gold, the traditional "safe haven" asset.
The online search term "buy Bitcoin" is now many times more popular than the equivalent "buy gold" term.
According to historic data, which accounts for total search volumes, "buy bitcoin" is now three times more popular than "buy gold" was even during the 2008-09 market crash - when consumers feared for the safety of their cash.
Commentators, professional investors and senior bankers have issued warnings over a Bitcoin bubbles. Royal Bank of Scotland chairman Sir Howard Davies told Bloomberg: "All the authorities can do is put up the sign from Dante's Inferno – 'abandon hope all ye who enter here'."
The Reserve Bank of India, the country's central bank, has issued three separate Bitcoin warnings since 2013. Last month the European Central Bank vice president said Bitcoin was a "speculative asset" where investors were "taking that risk of buying at such high prices".
Among investment bankers, JPMorgan Chase chief Jamie Dimon has been among the most vocal. In September he said Bitcoin was a "fraud" and anyone "stupid enough to buy it" would eventually pay the price.
Just last month, legendary index investor Jack Bogle told an audience in New York to "avoid Bitcoin like the plague".
Another milestone in Bitcoin's march into mainstream finance is expected in the coming days as two of the world's largest "futures" exchanges were given regulatory approval to list the currency.
CME Group and CBOE Global Markets are set to begin cryptocurrency trading from 10 December.
JP Morgan analyst Nikolaos Panigirtzoglou said that this move to join more formal financial markets “has the potential to elevate cryptocurrencies to an emerging asset class".
Futures contracts are a type of derivative in which two parties agree to make a transact under pre-agreed prices.
Many investors have now taken the view Bitcoin's ascent must end and are exploring how to make money if and when the crash comes.