An "Opera Overture" is a musical introduction to an opera, typically played by an orchestra. It sets the mood and tone for the performance, often summarizing key themes or motifs from the opera. The overture usually occurs before the first act begins, allowing the audience to immerse themselves in the musical world of the opera. Overtures can vary in length and style, ranging from short and lively to more elaborate compositions. Famous examples include the overtures from Giuseppe Verdi's La Traviata and Wolfgang Amadeus Mozart's The Marriage of Figaro. These pieces are essential for engaging the audience and preparing them for the story ahead.