Opera is a drama set to music. An opera is like a play in which everything is sung instead of spoken. Operas have arias which are songs for a solo singer and they have choruses which are sung by a group of singers. 

Opera singers have to have powerful voices as well as a good technique. Most opera houses are very big, and the singers need to be heard at the back. They also need to be good at acting. They need to be able to learn their music quickly and to sing from memory and they can sometimes have to sing in lots of different languages like Italian, German, French, English or Russian.

Casta Diva from Bellini’s opera ‘Norma’. Norma’s father wants to go to war, she is a priestess and here she sings an aria asking for peace. https://www.youtube.com/watch?v=g-6JhBYZCrw&list=RDjCw-p6qY7H4&index=14 

Oh mio babbino caro from Puccini’s  - no clips of this on an opera performance, tends to be sung in concert as a ‘favourite aria’ as so famous. Here is an outdoor concert in Paris under the Eiffel tower (start at 0.58) 

https://www.youtube.com/watch?v=FWuBCwS4B4E 

Queen of the Night from Mozart’s magic flute – has one of the highest notes sung in an aria (top F) – you need to be a coloratura soprano to sing this role. This version is sung in English (usually in German) – it is an angry song – she is trying to get her daughter to do something terrible! https://www.youtube.com/watch?v=RObyyjdA9ek