While Salzburg has plenty to offer visitors, it's also a great base for exploring the natural features and castles of the Austrian and Bavarian Alps. Organized Salzburg day trips make it easy to see spots inaccessible by public transportation. You can head out to the Salzkammergut lake district to see sites made famous by The Sound of Music, deepen your understanding of World War II history with a trip to the Kehlsteinhaus (Eagle's Nest), which was initially a Nazi meeting spot, or even check out Eisriesenwelt, the world’s largest ice cave.