Highlights: Barcelona Zoo is located in the Barcelona Castle Park, built in 1892 and covers an area of 13 hectares. It is one of the oldest and also modern zoos in the world today. The zoo is open-plan, allowing people to directly touch the animals. There are more than 400 species and 7,500 animals in the park. The animals on display include many animals from Africa and South America, and many of them are endangered species. Among the various monkeys living in the tropical rain forest on display, there is one kind of monkey that is very small, only about two-thirds the size of a human palm, which is extremely cute. There are also many rare animals in the night hall, such as night monkeys. What is even more rare is that there are native animals unique to Australia in the Barcelona Zoo, including a long tail that resembles a mouse and is said to be the world's smallest marsupial. In the reptile house, visitors can also see the world's poisonous spider "Black Widow".