The Botanic Gardens of Barcelona, originally established in 1930, were completely overhauled in the 1990s. They are now a beautifully landscaped green space that showcases Mediterranean-climate plants from all over the globe, including Africa, Australia, California, the Canary Islands, and Chile. The collection continues to evolve—new species are grown in greenhouses every year and planted in the gardens. The 71 planting zones are connected by walking paths, many of them crossing small bridges and walkways over ponds. If you’re also planning to visit the Museu de Ciénces Naturals (Museu Blau, across town in Parc del Forum), you’ll save some money by buying a combined admission. You can stroll through the stunning cactus garden on the other side (facing the port) of Montjuïc for free.