Three Natural History Museums took the initiative to start an internet site about natural history. They are the National Natural History Museum Naturalis (Leiden), the Royal Belgian Institute of Natural Science (Brussels) and the Hungarian Natural History Museum (Budapest). Now everybody can visit their collections in a digitized form. The site has an international character, and is therefore set up in four languages: Dutch, English, French, and Hungarian. Every collection pearl is illuminated with photographs and an essay, written by the scientists of the museum. In total 300 essays are available: about plants, animals, fossils, rocks and minerals, but also about archaeological and (paleo-)anthropological objects. In this article two of these pearls are briefly described: the mammoth of Lier (found in 1860, and the first reconstruction of a mammoth in a western European museum), and the forty woolly rhinos of Hofstade. The site bears the title “300 Pearls – highlights of natural diversity”, and its URL is