Milan, Italy - The 'Ndrangheta crime syndicate - based in Italy's southern Calabria region - is not nearly as well-known as Cosa Nostra, the Sicilian mafia. But the 'Ndrangheta organisation is wealthier and more powerful - with interests spanning the globe from Calabria to Colombia, and as far away as Australia.

According to Demoskopika, an Italian think-tank, the 'Ndrangheta's activities made a whopping $60bn in revenue in 2013 - more than the combined revenues of McDonald's and Deutsche Bank.

That's roughly three percent of Italy's GDP.

They have successfully exploited the Calabrian immigrants that headed to Germany, the US, Australia, Belgium, Colombia, and France after World War II. They used family ties to create new links and expand their influence worldwide. Antonio Nicaso, analyst

The 'Ndrangheta is estimated to control about 80 percent of Europe's cocaine traffic, and is believed to have invested in construction projects in Italy, Belgium, the United States, and Germany.

"The 'Ndrangheta is the perfect example of a globalised criminal network," said Antonio Nicaso, an expert on the group.

"They have successfully exploited the Calabrian immigrants that headed to Germany, the US, Australia, Belgium, Colombia, and France after World War II. They used family ties to create new links and expand their influence worldwide."

From kidnapping to cocaine

The 'Ndrangheta's operations began in the 1960s and '70s, focusing on kidnappings for ransom.

"This allowed the criminal organisation to accumulate an initial capital that at the end of the '80s was invested in cocaine," explained Ilaria Meli, a researcher at the Observatory of Organised Crime at the Universita' Statale of Milan.

"This decision represents a first turning point for the 'Ndrangheta, as it proved to be quicker than Cosa Nostra in understanding and exploiting a crucial shift of the drug market."

This strategy brought billions of dollars to the 'Ndrangheta's coffers.

"Today, their problem is that they have more cash than they can possible use," said Giuseppe Catozzella, an investigative reporter and the author of several books on the criminal syndicate.

In Alveare, Catozzella's book about the 'Ndrangheta published last year, one wiretap recorded a conversation between two mobsters. One of them was digging out a stash of money buried in a forest, and notified the other that "millions are rotten because of the humidity".

The other mobster replied nonchalantly: "Just throw them away."

The 'Ndrangheta's ascension was aided by a strategic mistake made by the Sicilian mafia.

At the end of the 1980s, Cosa Nostra embarked on an "anti-state" policy, culminating in the spectacular killings of top anti-mafia judges Giovanni Falcone and Paolo Borsellino in 1992.

The government reacted by deploying the army to Sicily and passing a new law that allowed imprisoned criminals linked to the mafia to be placed in solitary confinement.

"Those years were a lethal blow to Cosa Nostra's interest outside of Sicily," said Meli, "and they have started to reorganise themselves only over the past few years, as shown by a recent report from the DIA [Italy's anti-organised-crime unit]".

While the Italian authorities and media attention were focused on the Sicilians, the Calabrians were able to slowly but steadily expand into Italy's wealthy north.

Catozzela explained that in 1994, leaders of four major Italian mafias met at Lake Como to carve up the northern market.

"'Ndrangheta obtained 70 percent of it, a result that shows the power and influence it had achieved in just over two decades."

Exploiting opportunities

From Milan, in Italy's north, the rest of Europe is just a few hundred kilometres away. In the 2000s, the 'Ndrangheta was again able to take advantage of circumstances.

After the September 11 attacks, the Italian government diverted resources to the fight against "terrorism", allowing the Calabrian criminal organisation to operate with greater impunity.

Later in the decade, the economic crisis that hit much of southern Europe gave the Calabrian mob the opportunity to invest its illegal profits.

With thousands of cash-strapped businesses across southern Europe looking for liquidity, the 'Ndrangheta's only problem was deciding where to invest.

The Calabrian mafia appears to be based on Ndrine, with local groups that form the building blocks of the organisation.

All the Ndrine operating in any given geographical area - from Calabria to Australia - are believed to be organised in what are called Locali, which coordinate and mediate between the various Ndrine under their aegis.

The 391147, in turn, operate under the control of a higher representative body known as Il Crimine or La Provincia, which is based in Calabria and makes the organisation's top decisions.

The members of the La Provincia meet once a year, at the end of August, in Polsi, a small mountain town, where they celebrate the Madonna of Polsi and make important decisions for the coming year.

Every Ndrina, Locale and family operating outside of Calabria is thought to be linked to a similar unit back home. For example, investigations have shown that the Locale of Sterling, in western Australia, operated under orders coming from a Locale in Calabria.

Despite this vertical structure, the Locali enjoy a high degree of autonomy when it comes to conducting business.

But the structure of the 'Ndrangheta's hierarchy is not negotiable.

When Carmelo Novella, the head of the Lombardy 'Ndrangheta, tried to operate independently, he was killed in 2008 by one of the heads of the 'Ndrangheta in Calabria.

Not just an Italian problem

In the past, the 'Ndrangheta has benefited from being able to operate under the radar of Italian and European authorities. As recently as 2010, the then-mayor of Milan, Letizia Moratti, denied that organised crime groups operated in the city, even though it had been present in the region for about 30 years.

"In the north of Italy, organised crime is represented as a southern [phenomenon]; in the north of Europe, as an Italian problem," Meli summarises.

Italian police break-up mafia fraud

It was only in 2007, when a shoot-out in Duisburg, Germany was linked to the 'Ndrangheta, that German and then European authorities began to investigate the presence of the Calabrian syndicate outside of Italy.

The differences between European legal systems in dealing with mafia groups present one of the main difficulties in fighting groups like the 'Ndrangheta.

In 1994, Italy criminalised having relations with mafia organisations, but similar laws do not exist in some other European countries.

If, for example, the Italian police asked their counterparts in a neighbouring country to arrest a suspected mafioso, the police there may not be legally able to comply.

"There seems to be little will to accept that the 'Ndrangheta is a European problem," Meli said.

The 'Ndrangheta may no longer be able to avoid the attention of the authorities. But if its expansion beyond Italy is to be halted, experts agree that authorities throughout Europe need to cooperate more closely with one another.

"The 'Ndrangheta has become global, [but] the instruments to fight it have remained national," Nicaso concluded. "This is a problem that needs to be fixed - and quickly."