On the western edge of Nexø, the Bornholm Butterfly Park (Bornholms Sommerfuglepark) is a large tropical greenhouse where hundreds of free-flying butterflies from around the world share space with exotic plants. The warm humidity inside is a noticeable contrast to the Baltic air outside, and the butterflies land on visitors without much persuasion.
It is particularly popular with families with young children, though the collection of tropical species is genuinely interesting for any naturalist. The park also maintains a small exhibition on butterfly life cycles and migration. It sits just off the main road on the western outskirts of town and makes a good stop when arriving from or leaving toward the rest of Bornholm.