Today is World Wildlife Day, the UN-sponsored tribute to efforts that protect the plants and animals that make our world so special. This year"s WWD theme is "recovering key species for ecosystem restoration"—key species like the greater one-horned rhinoceroses you see here in northeastern India"s Kaziranga National Park. These unique creatures have staged a remarkable comeback from the verge of extinction in the early 20th century, when their numbers had dwindled to a precarious low of around 100 animals. But with the concerted efforts of Indian and Nepalese wildlife authorities, the population of greater one-horned rhinos has slowly built back up to around 3,700 today.