The country's forests sometimes seem like the biological equivalent of a cathedral; those giant tropical trees have the appearance of columns, and the canopy they support holds a collection of epyphitic vegetation more complex than the paintings on the ceiling of the Sistine Chapel. Mother Nature seems to work overtime in the tropics, and the consequent diversity of forests has been classified by biologists into a dozen different life zones. However, most of those forests can be lumped into three more general groups: rain, cloud and dry forests. Rain forests, with their massive trees, very high canopies and little growing on the dimly lit forest floor, can be found in the Atlantic lowlands and the southwest. The northwest contains some of the last remnants of the tropical dry forest, a less exuberant life zone that shares much of the diversity of the rain forests. Cloud forests, which cover the upper slopes of most mountains and volcanoes, are the most luxuriant of the tropical forests, with mosses and other small plants covering the trunks and branches of trees. They are all beautiful, and in many ways similar, but each one has plants and animals that won't be found in the rest.