Mammoth Cave, the world's longest known cave system. The following is a list of the world's 10 longest caves per length of documented passageways. Many passageways are still being discovered; this list is based on the latest verifiable data.
patent medicine - medicine that is protected by a patent and available without a doctor's prescription. medicament, medication, medicinal drug, medicine - (medicine) something that treats or prevents or alleviates the symptoms of disease. nostrum - patent medicine whose efficacy is questionable.
complementary medicine (complementary and alternative medicine (CAM)) a large and diverse set of systems of diagnosis, treatment, and prevention based on philosophies and techniques other than those used in conventional Western medicine, often derived from traditions of medical practice used in other, non-Western cultures.