Calabria, which forms the toe of the Italian boot, is a predominately mountainous region with marked variations in microclimates between the sunny coastal hills along the Ionian and Tyrrhenian seas and the chilly heights of the Sila and Aspromonte massifs. Two grape varieties of Greek origin dominate, Gaglioppo in red wines, Greco in whites. Calabria's best-known wine is Cirò, which grows in low hills along the Ionian coast between the ancient Greek cities of Sybaris and Kroton (Sibari and Crotone today).