Ciutadella Park is the largest green space within the old city. You won’t miss its impressive entrance, Arc de Triomf. It was built for the 1888 Universal Exhibition which was held in the park and has since become one of the city’s most iconic landmarks. Inside the park, you will find a serene boating lake, a stunning golden waterfall called Cascada Monumental, a zoo, and the Museum of Natural Science. Other attractions at this 70-acre park include a sculpture honoring Catalans killed in World War I and the huge mammoth sculpture.