Original: Individual songs from some of the operettas have become standards, notably "Vilja" from The Merry Widow and "You Are My Heart's Delight" ("Dein ist mein ganzes Herz") from The Land of Smiles.
Simplified: Some of the songs from his operettas have become very well-known, especially "Vilja" from The Merry Widow and "You Are My Heart's Delight" ("Dein ist mein ganzes Herz") from The Land of Smiles.