Berlin authorities are warning residents to keep doors and windows closed due to a large outbreak of processionary caterpillars. These caterpillars, dubbed “the larva from hell” by some, are known for their irritating hairs which can cause allergic reactions, skin irritation, and respiratory problems in humans and animals. The caterpillars travel in long lines, or processions, across the city, increasing the risk of exposure. City officials have cordoned off affected areas, particularly parks and forests, and are advising people to avoid contact with the insects. The outbreak is attributed to milder winters and climate change, allowing the caterpillars to thrive. Residents are urged not to attempt to remove the caterpillars themselves, but to contact local authorities for assistance.