Parnassius apollo prefers hills and flowery alpine meadows and pastures of the continental European mountains, also in Spain, Scandinavia and Central Europe, in the Balkans up to northern Greece and in the Alps between Italy and France.
   They require specific climatic conditions (cold winter, sunny summer), also require wide open spaces (with a cover of shrubs less than 5%) and a large surface of lawns (at least 50%). The presence of the host plant for the caterpillars is critical.
    (Typical of high altitudes, its range is from 400 metres (1,300 ft) up to 2,300 metres (7,500 ft), although it is far more present above 1,000 ft.)
   The Apollo butterflies show a great deal of individual variation in appearance, with an obvious color polymorphism.
   These large, beautiful and conspicuous white butterflies are decorated with five large black eyespots on the forewing and two bright red or sometimes orange eyespots on the hindwing. These striking red eyespots can vary in size and form depending on the geographic location of the Apollo butterfly, and the bright red color often fades in the sun, causing the eyespots of older individuals to appear more orange.
   The wings are shiny, with slightly transparent edges. Some individuals are darker (sphragismelanistic), a general phenomenon common in many butterflies.
   The caterpillars of this species are velvety black with orange-red spots along the sides.
   The adult Mountain Apollo flaunts large black spots on its forewings and mesmerizing red eye-spots on the hind wings, set against a backdrop of white to cream. This display of colors is not just for show; it plays a vital role in the butterfly’s survival.
    Similar to the monarch butterfly, the Apollo produces an unpleasant taste to predators.
They seem to get this foul taste from their host plants, the Sedum stenopetalum.
   There is an unpleasant bitter taste, which is found in both the butterfly and the plant. There is a much higher concentration of this taste in the wings as opposed to the rest of the body.
   The Apollo butterfly has many subspecies around the world, and some European subspecies are showing an alarming decline in numbers. This is mainly caused by habitat destruction, air pollution affecting the insect's food plants, and butterfly collectors.
   The Apollo butterfly is also more vulnerable to predators as it spends two years as a caterpillar.
   The Apollo caterpillar presents a striking appearance with its velvety blue-black skin dotted with vibrant orange spots. 
   * This species’ ability to adapt to various climates and elevations makes it a subject of interest in studies on climate change and habitat conservation.
   * There are 23 subspecies documented globally.
   * The Apollo is on the IUCN Red List of Threatened Species.
   The Apollo butterfly is named after the Greek and Roman deity Apollo, reflecting its divine beauty and the sunlight it thrives in.