One of the most prestigious racing tracks in Europe used to be situated between Rijeka and Opatija.
Opatija, a seaside resort town located southwest of Rijeka, is renowned for its 170 years of tourism history. One thing that don’t gets mentioned as often is the Opatija Circuit: a 6-kilometre long racing track that used to host auto races and motorcycle races between 1931 and 1977.
As Opatija happened to be under the Italian rule in 1931, the course was first known as Circuito di Abbazia (Opatija Circuit) and Circuito del Carnaro (Kvarner Circuit). It became internationally popular after hosting the 1939 Adriatic Grand Prix, almost by chance: as Benito Mussolini’s edict forbade the Italian team to participate in the French Grand Prix in Rheims, the team decided to compete in Opatija instead. Luigi Villoresi won the race driving a Maserati 4CL, turning the Opatija Circuit into a prestigious racing track overnight.
(Situation plan on the circuit, 1939)
The route was well-known for its picturesque scenery, but the narrow roads curving along the shore were its biggest drawback as well. Due to extremely unsafe driving conditions and roadside obstacles, multiple editions of the race resulted in tragic deaths of drivers; auto races were discontinued after the Formula 3 Gran Premio Adriatico in 1968. The following year, however, marked the beginning of the golden era of motorcycle racing after the Adriatic Grand Prix became a round of the FIM Motorcycle World Championship.
The 1977 Grand Prix was held in spite of an order from the FIM to improve the safety of the track. No modifications were made prior to the event and the race ended up with 19 injured and 2 fatalities, prompting the FIM to ban all road races from the World Championship schedule. The Opatija Circuit fame came to its end, and a modern replacement circuit was created in Rijeka.
(Grand Prix Yugoslavia, 1969)
Take a look at the video showing a part of the 1972 Grand Prix in Opatija:
Source: Formula 1 Dictionary