Greatest natural value of this park is the rainforest Biogradska gora, which covers the area of 1600 ha and is one of the last three rainforests in Europe. In 1878, it was donated to the then ruler of Montenegro, duke Nikola and from then on it remained – as a "duke’s reserve" – under the state protection.
The park has 26 plant communities with around 2.000 species and subspecies. Out of over 200 bird species, particularly interesting is the imperial eagle. Deer, fawn, leap, wolf, wild boar, fox, rabbit and over 350 different inspects species have found their habitat in the Park.
At the altitude of 1.094 meters, in the heart of the rainforest, there is Biogradsko Lake, the biggest and best known of the numerous glacial lakes in the area of the National Park. It consists of two parts, with numerous vortexes and typical glacial coves with unusual esthetic characteristics. Today, Biogradsko Lake is a famous excursion site with developed parking space, restaurant, bungalows, walking paths with lights and a camping space. Thanks to the climate conditions during summer months, it attracts a large number of tourists, particularly transit tourist, which stop here on their way to the coast, seeking refuge from high temperatures.