The crossword solution for the term 'Jungfrau is one' is ALP, which stands for the Alpine mountain range in Europe. The Alps are a mountain range that stretches across eight countries in Europe, including France, Switzerland, Italy, Germany, Austria, Slovenia, Liechtenstein, and Monaco. The highest peak in the Alps is Mont Blanc, located in France and Italy. Jungfrau is one of the most famous peaks in the Alps, located in Switzerland.