Background
Over the weekend of 15–16 February 2003 an Italian gang around Leonardo Notarbartolo broke into the heavily secured vault of the Antwerp Diamond Centre in Schupstraat. The thieves bypassed heat sensors, a magnetic alarm and a combination lock, among other things, and opened 109 of the 189 safe-deposit boxes. The haul of diamonds, gold and jewellery was estimated at more than $100 million, although Notarbartolo later claimed it was far smaller. Rubbish the thieves had dumped in a wood led police to him; in 2005 he was sentenced to ten years in prison, but most of the loot has never been recovered.
Sources: Wikipedia: Antwerp diamond heist · Wikipedia: Diamantroof van Antwerpen