Einstein on the Beach is an opera composed by Philipp Glass, his first and also longest opera piece, taking five hours for a full performance. It forms a trilogy of portraits along with Satyagraha (on Gandhi) and Akhnaten (the Egyptian pharaoh Amenhotep IV) who, in in the eye of the composer, "transformed the thinking of their times through the power of ideas rather than by military force".
The first recorded performance is that from the Théâtre du Châtelet in 2014 (270 minutes, or 4.5 hours). It is available as a playlist on YouTube.