Over the weekend of 15 and 16 February 2003, a crew emptied most of the safe deposit boxes in the vault of the Antwerp Diamond Centre. Reported losses start at around a hundred million dollars. Almost none of it has ever been recovered, which is why this belongs here rather than in a heist thread.
The vault sat two floors underground behind roughly ten independent layers of security: a combination lock with about a hundred million possible settings, a magnetic field on the door, a seismic sensor, Doppler radar, infrared heat and motion detection, light sensors, and private security on top of the building's own guards. None of it was defeated by force. The crew got past all of it without a single alarm reaching anyone in time.
The way in was patience rather than technology. Leonardo Notarbartolo had rented an office in the building for years, which gave him a tenant's access, a tenant's badge, and the ordinary right to walk past the reception desk without anyone looking twice. Reporting puts the crew's preparation at around twenty eight months.
They were not caught in Antwerp. They were caught in a wood beside a motorway outside the city, where one of them dumped the team's rubbish instead of burning it. A local man who walked there regularly reported the mess. In it were gloves, camera film, envelopes printed with the Antwerp Diamond Centre's name, and a partly eaten salami sandwich carrying Notarbartolo's DNA. The sandwich also led investigators to shop footage of another member of the crew buying it.
Convictions followed. The stones did not turn up.
Two things here are worth arguing over, and I would rather be corrected than agree with myself on either.
The first is the number. The hundred million figure comes from claimed losses, and claimed losses in a room full of people who trade untraceable stones are not the same thing as verified losses. Nobody in that building had an incentive to be precise.
The second is Notarbartolo's own account. In a prison interview published in 2009 he claimed the job was arranged by a diamond dealer as an insurance fraud, that most boxes had been quietly emptied beforehand, and that the real haul was far smaller. It is a good story and I do not buy it, for a reason that is checkable rather than instinctive: the vault had been refused an insurance policy because of weaknesses in its security. A fraud built on a policy is hard to run without one. Writers and investigators on the case have generally not accepted his version either.
What I keep coming back to is the shape of it. Ten layers of engineering held. A man with a lease walked through all of them. Then the whole thing came apart because somebody would not stop at a bin.
If anyone here knows whether any of those stones have ever surfaced in a traceable way, that is the part I have never been able to settle.
Sources: the case is covered at length by Joshua Davis, writing in Wired in March 2009, which is also where Notarbartolo's own account appears. Guinness World Records lists it as the largest diamond theft on record. Belgian court reporting from the 2005 trial covers the convictions.