A cheese made in the Franche-Comté region of western France, visually notable for its central line of charcoal. This doesn't appear to make any difference to its taste (having just tasted some).
It's a slightly stiff (but not hard), smooth, white cheese, with a light orange crust. I can't say I'm taken with it. It's got a fairly strong flavour but a little bit soapy, but maybe that's just my preference in cheeses. The second website I cite below calls it "savoury and fruity"...? No, I can't really go along with that.
It was created in the 19th century in the village of Morbier (or Morbez?) in the Jura Mountains; each night they sprinkled soot on the remaining curd. Spare cheese was then placed on top. This compacted and produced the characteristic inner black line. In fact, local records date from 1795 referring to a cheese in Morbier, and a letter of 1799 says they were trying for a gruyère effect -- but it's nothing like a gruyère!
http://www.fromage-morbier.com/ (official site, in French)