The Atacama Desert in South America is peppered with odd, cushion-like plants known as the llareta, a spongy cousin of parsley. Despite the harsh weather conditions that they have to endure, some of these plants are up to 3,000 years old. Though looking like a rock covered by small green plants without flowers, the plant has a tightly packed structure of branches, each adorned with clusters of tiny leaves. The resulting plant is so strong that you can stand on top of it very comfortably. However, this hardiness comes at a price: the plants are thought to grow just 1.5 cm a year. According to Catherine Kleier, a researcher from Regis University, Colorado, the llareta became very strong because of a combination of environmental factors (cold at night and hot in the day) and it is compact to trap heat. The more compact the plant, the more successfully it protects itself.