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.
patent medicines. medicines sold directly to the public. Opium Wars. war between Great Britain and China, began as a conflict over the opium trade, ended with the Chinese treaty to the British- the opening of 5 chinese ports to foreign merchants, and the grant of other commercial and diplomatic privileges.