Playa de Arena Blanca is a stunning white sand beach on Bioko Island in Equatorial Guinea. But that’s not the only reason to visit. During the dry season between December and February, thousands of butterflies populate the beach to breed. The spectacle is known to create dense “clouds” of butterflies.

Bioko Island is the largest volcanic island in the Gulf of Guinea, located 100 miles northwest of Equatorial Guinea’s coast and 60 miles from the southern coast of Nigeria. In the native Bube language, the island is called Ëtulá Ëria. Much of its landscape is dominated by tropical rainforests and steep mountains.

That landscape supports a diverse population of plants and animals. The island is home to more than 200 species of birds, and its beaches are a breeding ground for four species of sea turtles. Interestingly, a 1994 analysis found that Bioko has fewer endemic species (plants and animals found nowhere else) than the nearby islands of São Tomé and Príncipe. These other islands in the Gulf of Guinea have been isolated for much longer, while Bioko was connected to the African mainland until about 10,000 years ago.

Bioko also has some of the greatest butterfly diversity in the world. In 2000, 172 different butterfly species were recorded on the 779-square-mile island, and researchers continue to learn more about the fluttering insects that call this island home. In 2015, researchers identified three new species on the island that sport some extraordinarily cool names: the striped policeman (Coeliades forestan), the silky dart (Semalea pulvina), and the forest sylph (Ceratrichia phocion camerona).