Just 84 Amur leopards remain in the wild, making it one of the world's rarest and most endangered big cats. It's also one of the most attractive, with a distinctive patterned coat with black splodges and flecks that sets it apart from other leopards. If you're very lucky, you may be able to find this critically endangered cat in Russia's Primorsky Krai or north-east China's Jilin Province. ¹⁾

The Sumatran rhino, like the Javan rhino, is one of the world's most endangered rhino species. It is also the tiniest. Less than 80 are left in small populations in Sumatra, Borneo, and the Malay Peninsula.²⁾

The Hainan gibbon is endangered due to poaching and habitat destruction, with just 30 individuals remaining, making it the world's rarest ape. The Bawangling National Nature Reserve on China's Hainan Island is the only location where you can see one. This is home to the last surviving population, which is restricted to a single spot within the forest. ³⁾

Despite the fact that the mountain gorilla population has grown in recent years, due to WWF conservation efforts, seeing a gorilla in the wild is still a very rare occurrence. This is mainly due to the gorillas' position and the cost of getting to them. Only the most daring travelers choose the Democratic Republic of Congo, while those who are more concerned about security choose Rwanda or Uganda. Having these primates in the wild is an exciting experience since they are the biggest of the great apes and share over 98 percent of their genetic code with humans. ⁴⁾