‘Seven Sister’ states of Assam, Arunachal Pradesh, Meghalaya, Mizoram, Manipur, Nagaland and Tripura. Here are some marvellous facts about the Northeast region as a whole. Around 220 languages are spoken in the states of the Northeast. The Northeast India has been identified as one of the world’s seven richest biodiversity areas by Myers 2000. The world’s largest riverine island, the Majuli, is in the Northeast. The River Brahmaputra that criss-crosses the Northeast is the only Indian river that passes through three countries. The language and culture of Northeast is a mix of Tibetan, South-East Asian and East Indian culture. The Indian Rhinoceros, also known as the one-horned rhino, is found exclusively in the Northeast. Mizoram and Tripura are among the states with the highest literacy rates in India.