The Faroe Islands generally have cool summers and mild winters, with a usually overcast sky and frequent fog and strong winds. Although at a high latitude, due to the Gulf Stream their climate is ameliorated. The islands are rugged and rocky with some low peaks; the coasts are mostly bordered by cliffs. The Faroe Islands are notable for having the highest sea cliffs in Europe, and some of the highest in the world otherwise. The lowest point is at sea level, and the highest is at Slættaratindur, which is 882 metres above sea level. The landscape made roadbuilding difficult, and only recently has this been remedied by building tunnels.