What's in the box? Mystery of giant Amazon delivery solved

An image of the Amazon delivery appeared on the Reddit website on Monday (Imgur)

The mystery of the “biggest Amazon box ever” spotted in a residential street in the US has been solved.

The image of an oversized box on the back of a flatbed lorry in Madison, Wisconsin, appeared on the Reddit website on Monday, sparking speculation as to what may be contained inside - and indeed whether the picture was a fake.

One Reddit commentator joked: "Given amazon's packaging efficency, it's probably a usb key."

Other suggestions included a particle accelerator, bowling alley and a military tank.

But it has emerged that the stunt was part of an advertising campaign for the Nissan Versa Note.

The online retail juggernaut worked with the car manufacturer in September to allow shoppers to buy cars through a promotional link on the Amazon homepage.

The first 100 buyers got a $1,000 Amazon gift card and three people got their new cars specially delivered.

Film crews even joined the lorry to film the huge delivery.