The town of Zermatt lies at the southern end of the Matter Valley (German: Mattertal), which is one of the lateral branches of the grand Valley of the Rhône. Zermatt is almost completely surrounded by the high mountains of the Pennine Alps including Monte Rosa (specifically its tallest peak, named Dufourspitze), Switzerland's highest peak at 4,634 metres (15,203 ft) above sea level. It is followed by the Dom (4,545 m [14,911 ft]), Liskamm (4,527 m [14,852 ft]), Weisshorn (4,505 m [14,780 ft]) and the Matterhorn (4,478 m [14,692 ft]). Most of the Alpine four-thousanders are located around Zermatt or in the neighbouring valleys.Zermatt is traversed by the main river of the valley: the Matter Vispa, which rises at the glaciers at the feet of the highest peaks: the Gorner Glacier on the east side near Monte Rosa and the Zmutt Glacier on the west side between Dent d'Hérens and Dent Blanche.