In 2015 Max Richter released an 8.5 hour album composed using neuroscience research about the sleep cycle. Its length is designed to cover the sleep stages experienced during a full night's rest as it takes you through first falling asleep, into REM, and gently mimics waking up.
He performed the album live with a rotating orchestra stepping in and out throughout the whole eight hours, surrounded by sleeping people.
There's a wonderful documentary about it (trailer in link). The album is on Spotify. I put it on nightly during a period of insomnia during lockdown and found it very soothing.
