In a history stretching back over 100 years, Alfa Romeo has been responsible for some of the most desirable Italian cars ever, with their most sought-after models fetching over a million dollars at auction today. Ever since they entered their first production car, the 24 HP, into the Targa Floria in 1911, they've established themselves as a dominant force in motorsport. At the same time, they've honed their talent for combining luxury and performance to make their passenger cars irresistible to generations of drivers.

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Over the years, they've made a huge variety of cars, more than most enthusiasts might realize. For example, in the late '40s, Alfa released a military vehicle that looks like a Jeep, and before that, they made an experimental racing prototype that looked like an Airstream caravan on four wheels. It's not just unusual designs that have become lost over time either, as some of the brand's most beautiful cars have been mostly forgotten about by all but the most dedicated brand enthusiasts. So, let's take a look at ten of the rarest Alfa Romeos from their back catalog that don't deserve to be forgotten.

10 1900C Super Sprint

Alfa Romeo 1900 C Super Sprint
Via RM Sothebys

The 1900 was one of the first Alfas to employ unitary construction, and it could be commissioned with a choice of two body styles, either a cabriolet by Pinin Farina or a coupe by Touring. A short-chassis version was also available, named the "1900C".

Alfa Romeo 1900 C Super Sprint
Via RM Sothebys

The Super Sprint was an upgraded version of the 1900C, with a more powerful version of the standard car's four-cylinder motor. Very few units were made and even fewer survive until the present day, making examples like the one pictured very desirable among collectors.

9 Spider Beauté

Alfa Romeo Spider Beaute
Via H and H Auctions

Only 120 examples of this limited-edition Spider were ever made, and they were specific to the French market. Designed in collaboration with Parisian fashion designer Jean-Louis Scherrer, the car featured a distinctive white and dark blue color scheme that set it apart from the regular Spider.

Alfa Romeo Spider Beaute
Via H and H Auctions

No mechanical modifications were made to the car, which meant the 2.0L engine remained from the standard model. Each car came with a number plaque to denote its place in the series, with all 120 units sold quickly upon their debut.

8 Tipo 33 TT12

Alfa Romeo Tipo 33 TT12
Via Wikimedia Commons

Alfa Romeo's Tipo 33 nameplate was used to denote a series of prototype racers from the Sixties and Seventies that became known for their stunning looks as well as their performance. The TT12 was somewhat the ugly duckling of the lineup, although its pace was undeniable.

Alfa Romeo Tipo 33 TT12
Via Wikimedia Commons

It made its competition debut in 1973 with a 3.0L flat-12 engine and won the Monza 1000km endurance race the first year it entered. It also won the manufacturer's title in the 1975 World Sports Car Championship, dominating the season and winning 7 out of 8 races.

7 156 GTA

Alfa Romeo 156 GTA
Via Historics Auctioneers

One of Alfa's more recent forgotten creations, the 156 entered the market just as saloons were starting to lose market share to SUVs and crossovers. The GTA was the top-spec variant and was sold in both saloon and wagon form, with around 3,500 examples built in total over 4 years.

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Alfa Romeo 156 GTA
VIa Historics Auctioneers

It featured a different engine to the regular 156, with its 3.2L V6 being developed by the Fiat-Maserati Research Center. In addition, it had several other upgrades as standard, including a revised steering setup and racing Brembo brakes.

6 6C 2500 SS

Alfa Romeo 6C 2500 SS
Via Thiesen

The 6C name was used on a variety of Alfa Romeo's road and competition cars between the late '20s and the '50s to signify the model's straight-six engine. The 2500 SS is one of the rarest variants, with only 68 short-chassis cabriolets ever built.

Alfa Romeo 6C 2500 SS
Via Thiesen

The car's chassis was built by Alfa Romeo and then sent to Pinin Farina for the bodywork to be constructed. The cars became a hit with celebrities around the world, and many examples including the one pictured were shipped off to America shortly after being built.

5 33 Stradale

Red Alfa Romeo 33 Stradale
Via: Alfa Romeo

Probably the most well-known of the "Tipo 33" racers is the 33 Stradale, as it's not only one of the rarest Alfa Romeos ever built but surely one of the best-looking too. Even though it's not the most obscure model here, it's still a bit of a hidden gem that only brand enthusiasts and classic car aficionados are likely to remember.

Red Alfa Romeo 33 Stradale ina garage
Via Alfa Romeo

It's a road-going version of the Tipo 33 competition car, and it's widely regarded as one of the first true supercars ever. Only 18 examples were ever made, and they're so rarely seen at public auction that it's almost impossible to estimate their current worth. However, the figure is likely to be in the tens of millions of dollars.

4 40/60 HP Aerodinamica

Alfa Romeo 40-60 HP Aerodinamica
Via Museo Alfa Romeo

One of the oddest looking Alfas ever produced, the 40/60 HP Aerodinamica was commissioned by an Italian businessman and built by coachbuilders Carrozzeria Castagna. The idea was to create a prototype that would be capable of speeds previously unheard of through the use of aerodynamics.

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Alfa Romeo 40-60 HP Aerodinamica
Via Wikimedia Commons

The focus on aero is the reason for the car's unusual shape, and despite its odd looks it was seriously fast for its era, achieving a top speed of 86 mph. A replica of the original car is now on display at the Alfa Romeo Historical Museum in Milan.

3 164 QV

Alfa Romeo 164 QV
Via Alfa Romeo

The QV or Quadrifoglio Verde badge is well known to Alfa enthusiasts as the sign of a great car, and the 164 QV is no different. The car came with Alfa's signature "Busso" V6 engine that made roughly 197 hp and 202 lb-ft of torque.

Alfa Romeo 164 QV
Via Alfa Romeo

It's an excellent example of the boxy '80s design that's started to become desirable again in recent years, and what's even better is most examples of the car came with a two-tone paint scheme like the example here. These cars are a bit of a bargain at the moment with mint-condition 164 QVs selling for as little as €10,000 ($10,984).

2 1900 M Matta

Alfa Romeo 1900 M Matta
Via MM Garage

Alfa is best known for their luxury performance cars and stunning grand tourers, so it might come as surprise to some that they made a Jeep-style military vehicle for the Italian military in the early 1950s. The 1900 M, or "Matta" as it was commonly known, was developed in response to a request from the Italian Ministry of Defence.

Alfa Romeo 1900 M Matta
Via MM Garage

Just over 2,000 examples were made for military, use, but there were also a very small number of civilian versions sold too. It's thought just 154 civilian examples were sold between 1952 and 1954, making this one of the rarest road-going Alfa Romeos of all.

1 Giulia Sprint GTA

Alfa Romeo Giulia Sprint GTA
Via Girardo & Co

The regular Giulia of the Sixties was already a great-looking car, but the rare Sprint GTA variant made it look even cooler. It was built as a homologation requirement and only 501 examples were made, as competition rules at the time dictated that a minimum of 500 examples had to be produced.

Alfa Romeo Giulia Sprint GTA
Via Girardo & Co

The car is significantly different from the standard Giulia and shares many parts with the competition car. Every little detail was considered to make the car as lightweight as possible, and even skinnier door handles were used to shave those last few pounds off.