There are some cars that are uncommon to see, but there are some that are so rare that you will probably never actually see them. These cars are usually kept as collectibles, sometimes shown off at shows and museums, but they don’t often make it to the streets. Every car on this list has two things in common: they are made in impressively low production numbers, and they are some of the most expensive cars on the planet.

Ferrari 250 GT Spyder Convertible

If you were to see the Ferrari 250 GT Spyder convertible you might not recognize just how rare and valuable the car is. With only one model ever produced as a convertible, it is the rarest Ferrari ever. It is so rare that we can only guess at to how valuable the car actually is, and it could be anywhere between $10 million and as much as $20 million.

Rolls-Royce 15 hp

The Rolls-Royce name itself screams rare and expensive, so you shouldn’t be surprised to see one of its cars on the list. The Rolls-Royce 15 hp goes beyond antique, it’s almost ancient in the world of cars with a production date of 1905. There were only 6 of these cars ever made, and plays a major roll in Rolls-Royce history as it was one of the first cars created with the collaboration of Charles Rolls and Henry Royce.

Porsche 916

You can find a handful of classic and antique Porsche cars for a bargain and get great handling and performance, but there are some Porsche cars that are almost unattainable. The Porsche 916 is one of these rare and collectible cars, and they have a going price of around $3 million dollars – that’s more expensive than any brand new Porsche today, including the Porsche 918 Spyder – Porsche’s leading supercar.

Mercedes 300SL Gullwing

The Mercedes 300SL Gullwing is a stunning part of the Mercedes heritage, and it comes with a collector price tag of around $3 million dollars – yikes. It had iconic Mercedes styling that you can recognize even in modern Mercedes-Benz cars today and was beautifully designed with gullwing doors to make it even more exotic.

Aston Martin Bulldog

As an avid Aston Martin fan, I was surprised to find such an unusual piece of the collection that even I had never heard of, and I was shocked to see what it looked like. The Aston Martin Bulldog isn’t the most expensive car on this list, usually selling at auction for a mere $1.5 million dollars

There are a surprising amount of rare, collectible cars throughout history, and even if we don’t see them often – or really, at all – they still play important roles in the history of each car manufacturer, and give us something novel to appreciate, even if it’s just as a car museum or in pictures.