Today's the day for Tesla. The automaker says it expects to complete production of "SN1" (or "Serial Number one") of the Model 3, its first electric car for the masses. But the Model 3 isn't just any car. Everything for the success of Tesla as a viable car company has been building up to this point. The Model 3 will define the future of the company — and the stakes for Tesla and CEO Elon Musk couldn't possibly be higher.

Earlier this week, Musk tweeted that Friday was the day the first Model 3 would be rolling off the assembly line. In subsequent tweets, he added that the first 30 Model 3 customers will receive their new Teslas on July 28th at a handover party hosted by the automaker.