- Child porn -

German police shut down "one of the biggest darknet child pornography platforms in the world" and arrested four of its members in a series of raids in mid-April.

The "Boystown" platform counted over 400,000 members and was "set up for the worldwide exchange of child pornography," according to federal police.

The months-long, German-instigated operation was coordinated by Europol and supported by detectives in the Netherlands, Sweden, the United States and Canada.

- Migrant smuggling -

An operation led by Interpol last year targeting migrant smuggling and human trafficking networks led to more than 200 arrests and the identification of some 3,500 irregular migrants worldwide.

Operation Turquesa II took place from late November to early December and saw authorities in 32 countries follow leads from national investigations.

- Paedophile ring -

Nearly 900 suspected paedophiles were arrested and almost 300 children identified or rescued from their abusers in 2017 following the massive takedown of an underground online paedophile network.

The two-year investigation by the FBI and Europol into the notorious Playpen network led to the arrests while a US court sentenced Playpen founder and administrator Steven Chase to 30 years in jail.

Dubbed "Operation Pacifier", the investigation began when the FBI used its own malware to effectively seize the Playpen website and server.

Operating it for several weeks, investigators then hacked and tracked site users by sending malware to their computers.

In an operation that critics say was legally questionable, more than 1,000 computers worldwide were hacked in this way by the FBI.

- Child trafficking -

In an unprecedented swoop on organised crime groups across Europe in 2014, police arrested more than 1,000 suspects and rescued at least 30 trafficked children.

The continent-wide raids targeted gangs involved in people trafficking, cybercrime, narcotics and illegal gun running.

With 20,000 officers involved, Operation Archimedes "was the single largest coordinated assault an organised crime in Europe," according to Europol.

Police officers from all European Union members as well as Australia, Colombia, Norway, the US, Serbia and Switzerland, carried out 250 operations in some 300 cities.

- Massive drug sweep -

US and Mexican investigators arrested 750 people over 21 months in a huge anti-drug sweep in 2009, including 52 members of Mexico's notorious Sinaloa drug cartel.

Operation Xcellerator -- which also covered Canada -- netted some $59 million in cash, 12 tonnes of cocaine, 544 kilos (1,200 pounds) of methamphetamine and 1.3 million ecstasy pills.

The raids uncovered machines able to produce 12,000 ecstasy tablets an hour.

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