Ford is announcing on Wednesday that it has made its 10 millionth Mustang, the best-selling two-door sports car that has been in continuous production since it was first introduced 54 years ago.

On Thursday, the second-largest U.S. automaker will unveil its new Nascar Mustang, which will replace the Fusion sedan Ford is phasing out of U.S. production.

It all speaks to the enduring influence power of the brand, which some at Ford say has become essential to Ford's identity, even in an era when buyers are turning away from traditional cars. Ford recently raised more than a few eyebrows when it said it was going to stop making most sedans and compact cars. But it's holding on tight to the Mustang.

This is in no small part because Mustang is practically a brand unto its own. It reliably delivers. It has been the best-selling two-door sports car around the world for three years running.

It can be bought for little more than $20,000, or more than $50,000. It can be sold to rental car agencies or to racing enthusiasts. It remains one of the most easily modifiable cars — there is a vast ecosystem of aftermarket parts suppliers and shops that will work on the car.