Sixty-six people have been arrested in Spain in an operation against child pornography, police say.
One person had 21 separate hard drives to store their pornography
Officials said computers containing 48m child pornography images and videos had been seized in the operation, which was co-ordinated by Interpol.
Those arrested reportedly include doctors, lawyers and teachers.
Officers are now trying to establish whether any of the suspects have themselves committed child abuse acts.
The investigation began in September after German police told Spanish police about several child-sex internet forums being accessed by individuals in Spain.
Under Operation Penalty, which was co-ordinated by Interpol, Spanish police monitored 5,000 downloads of material from servers based in Germany.
The investigation identified 85 suspects, most of whom are now in custody.
Police said that one of those arrested possessed the largest child pornography haul ever found on one person, a collection which needed 21 separate hard discs to house it.
The operation was so large that it involved 300 specialist agents and covered 40 of Spain's 57 provinces.