Nebbiolo is an Italian red wine grape, grown most commonly in the Piedmont region of Italy (north east corner, closest to France). The famous wines of Barolo and Barbaresco are made from Nebbiolo grapes. Named after and long thought as the most noble of native Italian grapes, Nebbiolo has garnered the highest prices for generations. Like many of the most expensive wines in the world (Cult Cab's from Napa, Bordeaux and Burgundy) Nebbiolo benefits from significant bottle aging and can be cellared for decades given peak conditions and a good vintage.
Outside of Italy, many regions have tried to grow Nebbiolo, without success. Most sites, including famously those tries in Australia, have simply been too hot. Current research and plantings show renewed interested in Australia as well as lesser known wine regions such as Baja California.