A botanical garden is located in the northwest side of Madrid, and is characterized as a forested area, that is, it is full of trees. It is also home to a wide variety of birds, with more than 70 species having been spotted, making it one of Madrid's most valuable parks. Visitors to the park, and locals, see it as a real piece of forest within the city. During the reign of Queen Isabel II, the garden was replanted with pine trees, especially rock pine, and black pine, which is now the most common species in the garden. In addition to walnut trees, especially bitter almonds, acacia trees, and others.