Hot air balloonists treated sleeping Birmingham residents to a special dawn chorus meant to stimulate their dreams.
The event was part of an artist's experiment on sleep psychology
The specially devised music was piped from seven hot air balloons which drifted low over the city on Thursday.
Hundreds of people went into the streets to watch the Sky Orchestra pass over after it took of at 0630 BST.
Sleep psychologists designed the medley for the event which was part of the city's bid for Arts Council cash.
The £15m fund for promoting cultural events is backed by Fierce!, an international festival of live art which runs until 12 June.
Festival director Mark Ball, who joined the hour-long flight, said: "The response was absolutely fantastic.
"You could see people running out of their homes to watch, some just wrapped in towels.
"Birmingham is not really a ballooning city, so it was an extraordinary sight for people to see these balloons floating between tower blocks and playing this
Each of the balloons played a different part of the musical score through speakers as they flew over Highgate, Balsall Heath, Moseley and Kings Heath.
The sounds combined to create a "musical landscape" like calling whales.
A leaflet warning people about the event had been delivered to homes under the flight path.