The heist in April targeted the Hatton Garden Safe Deposit Ltd., which has been "the epicenter of London's jewelry trade since medieval times." Police believe it took days. This hole through a vault wall is about 10 inches high and 18 inches wide. The wall is composed of 20 inches of reinforced concrete, so the drilling alone likely took a while. Metropolitan Police Service

There was no sign of forced entry on the outside of the building , which houses numerous businesses. It appears the thieves disabled an elevator on the second floor of the building, then climbed down the elevator shaft into the basement where the vault is located, said Detective Chief Inspector Paul Johnson of the London Metropolitan Police's Flying Squad. The squad, which Brits often refer to as "The Sweeney," is the Met's branch dedicated to heists and armed robberies. "Sweeney Todd" is Cockney rhyming slang for Flying Squad. Get it? No? It's OK. Few non-Cockneys do. Metropolitan Police Service

Here's the hallway leading to the vault. By now you're thinking, "Doesn't this joint have alarms?" Yes, it does. In fact, an alarm was activated, recorded and transferred to a computer-aided dispatch system used by police. However, the alarm had a "grade" that meant no police response was required , according to investigators. Even though police say it's too early to determine whether applying the correct grade would have stopped the heist, you have to think someone has some explaining to do here. Metropolitan Police Service

The thieves cut through the bars of a security door. Police say this must have taken some time. How long is unclear, though, as the Met said in a statement that the thieves accessed the vault between 9:20 p.m. on April 2 and 8:05 a.m. on April 3 and between 10:17 p.m. on April 4 and 6:30 a.m. on April 5. For the math-challenged, that first window is almost 11 hours; the second, more than eight. Metropolitan Police Service

The vault is protected by a pretty intimidating door, which is probably why the thieves opted to bore through a concrete wall instead. Though little information is known (or being released) about the suspected robbers, London's Daily Mail has already given them nicknames such as Mr. Ginger and Mr. Montana. Very "Reservoir Dogs" of them. The paper further reports that the thieves were dressed like utility workers, their faces were covered and they carried large bags with tools, though CNN hasn't been able to confirm those details. Metropolitan Police Service

Here is a photo of what bank robbers call "pay dirt." Obviously, the police didn't release the deposit box owners' names, but given the company's location, it's safe for police to say many of the boxes' owners were in the jewelry trade. Metropolitan Police Service