Police in Spain on Tuesday said that they had seized more than one million ecstasy pills and other narcotics worth more than 25 million euros.
They called it the biggest ever seizure of synthetic pills in the country.
Officers arrested nine people as part of the operation in the southern city of Malaga and the holiday island of Ibiza suspected of belonging to "one of the main criminal organisations involved in the introduction of synthetic drugs in Spain, which operated in different parts of Europe," police said in a statement.
Police said the gang was headed by Italian nationals based in Ibiza, which is known for its beaches and glittering dance clubs where party drugs like ecstasy are commonly found.
They seized 1,071,327 ecstasy pills, 73 kilogrammes of MDMA -- the primary psychoactive chemical constituent of ecstasy -- 212 kilogrammes of ketamine, 20 kilogrammes of cocaine, 21 kilogrammes of "pink cocaine", which is a mixture of synthetic drugs, 10 kilogrammes of hashish and six kilogrammes of marijuana.
"This is the biggest seizure of synthetic pills ever made in Span," the statement said.
Police suspect the gang used vehicles with false bottoms to smuggle the drugs into Spain.
The country is a main entry point for drugs into Europe given its close ties with its former colonies in Latin America, a major cocaine producing region, and its proximity to Morocco, a top cannabis producer.