Opera is a genre of classical music that was born in Italy. Some people regard it as the highest form of musical expression, because opera singers are able to hit notes so high they sound like birds singing. There are many different types of operas and each one has its own unique story line. Here are five famous opera singers you should know about: Luciano Pavarotti – This Italian tenor was one of the best-known operatic artists in history, selling over 80 million records worldwide. His most famous song is “Nessun Dorma”, which he sang at two World Cup soccer games in 1990 and 1994 for an estimated 1 billion viewers worldwide! Madama Butterfly – This opera tells the story of Cio-Cio San (also known as Madama Butterfly), an innocent Japanese girl who falls madly in love with an American man named Pinkerton after he promises to marry her and take her back to America with him; but later, when she discovers his true intentions, she kills herself by stabbing herself with his knife. Ana María Martínez – She was the youngest person ever to win the Richard Tucker Award in 2006. Her voice is described as “glorious” and she sings a wide range of roles from soprano to mezzo-soprano parts. Joyce DiDonato – She plays both male and female characters with ease, which makes her incredibly versatile. Her debut album was named one of the best classical albums by iTunes in 2011. Gerald Finley – An English bass-baritone who sings roles from Mozart’s operas as well as Wagner’s “Ring Cycle” among others. He also sings everything from Baroque music by Handel and Bach to contemporary works by John Adams.