Monte Rosa (Italian: ; also used in German) or Mont Rose (French: ) is a huge ice-covered mountain in the Alps, located on the watershed between northern and southern Europe. Its main summit, named Dufourspitze in honor of the surveyor Guillaume-Henri Dufour, culminates at above sea level and is followed by the three nearly equally high subsidiary summits of Nordend, Zumsteinspitze and Signalkuppe. Monte Rosa is the highest mountain of both Switzerland and the Pennine Alps and is also the second-highest mountain of the Alps and Europe outside the Caucasus. As a massif, Monte Rosa straddles the border between Switzerland and Italy, although its main summit, unlike the three lower ones, lies on the Swiss side, within the canton of Valais.