Authorities arrested 17 people and shuttered more than 400 cyber marketplaces operating on the dark net around the world, according to Europol.
The sites sold all manner of illegal goods, including drugs, weapons, and child pornography, Europol said.
"In addition, bitcoins worth approximately $1 million ... in cash, drugs, gold, and silver were seized," Europol said.
The raids came on Thursday – the same day U.S. authorities arrested Blake Benthall, accusing him of running the marketplace Silk Road 2.0 – and were announced Friday.
The sites largely used Tor, which masks users' IP addresses.
"We are not 'just' removing these services from the open Internet; this time we have also hit services on the dark net using Tor where, for a long time, criminals have considered themselves beyond reach," said Europol's Troels Oerting.
"We can now show that they are neither invisible nor untouchable. The criminals can run but they can't hide."
Sixteen European countries helped bring down the sites, Europol said, including Bulgaria, Czech Republic, Finland, France, Germany, Hungary, Ireland, Latvia, Lithuania, Luxembourg, Netherlands, Romania, Spain, Sweden, Switzerland, and the United Kingdom.
Meanwhile, Business Insider reported that Silk Road 3.0 has already been created.