Nobody's really sure, because the company won't comment on it, and Apple is famous for keeping its research and development projects under wraps.

But its hard to keep a project of this size a secret. Even Tesla CEO Elon Musk says it's an "open secret" that Apple has obvious automotive ambitions. 

There are a lot of rumors and gossip about the Apple Car. We've collected the best below so they're all in one place:

Do you know anything about Project Titan or Apple's car? Email the author at kleswing@businessinsider.com.

The rumors first started to fly in February 2015, when the Wall Street Journal reported that Apple had "several hundred employees" working on an "Apple-branded electric vehicle" called Project Titan.

According to the report, the vehicle looks like a minivan. Senior Apple executives have met with Austrian contract managers including Magna Steyr.

The thing is that Apple doesn't actually do any manufacturing, unlike car companies like Ford or Tesla. It contracts the assembly of devices like the iPhone to third-party factory companies like Foxconn.