What just happened? Over the weekend, someone paid almost $40,000 for a smartphone. No, it wasn't gold-plated or diamond encrusted. It didn't even have decent specs — a two-megapixel camera, less than 32GB of storage, and a 3.5-inch display. So what made it so valuable? It was an unopened first-gen iPhone.

Business Insider reported that someone paid $39,339.60 for an iPhone on Sunday. The seller listed the first-generation handset in its factory-sealed box with LCG Auctions on September 30.

"Collectors and investors would be hard-pressed to find a superior example," read the listing. "Relevance and rarity comprise a winning formula for this red hot collectible."

Bidding for the vintage 2007 Apple device started at $2,500. The auction house estimated the phone would sell for at least $30,000. Bidding reached about $10,446 just days before closing and stagnated. However, last-minute buyers fiercely competed as the deadline drew down, ratcheting the winning offer to over $39,000 in just 13 bids.

The 15-year-old phone probably has a stone-dead battery (possibly bloated and unusable), but that should not matter as the collector who bought it is not likely to open it to find out. The "pristinely" packaged device was the 8GB model, which sold for about $600 with a two-year AT&T contract in 2007 — that's about $860 today. So the buyer paid more than 45 times its original cost when adjusted for inflation.

Look how cute the iPhone was in 2007.

Why would someone pay so much for a device they won't even use and which pales in functionality and power compared to contemporary counterparts?

Collectors are a hard bunch to figure out. Someone bought an Apple-1 computer signed by the Woz earlier this year for $480,000. Some auction-goers likely speculated they could get more for the item years later. Others just have a deep desire to own a part of history. Both the Apple-1 and the iPhone 1 certainly fit that bill.

When Steve Jobs unveiled it on January 9, 2007, at the MacWorld Expo, there was no other phone like it. It became Apple's best-selling product and shaped the future of all smartphones to come after it.

"[The iPhone is] one of the most important and ubiquitous inventions of our lifetime," said LCG in the description. "[It] was named the Time Magazine Invention of the Year in 2007."

It is unknown how many first-generation iPhones are still in the wild, let alone ones that are still factory sealed, but it's safe to say they are rare. Chances are the buyer is holding a valuable piece of history that will be worth more in the years to come.