The fire is believed to have begun in a toilet at the Edward's No.8 club in central Birmingham.
More than 500 people were led to safety from the club and 10 were treated for smoke inhalation as the flames quickly spread from the third floor to the roof.
Ten fire engines and 50 firefighters were sent to the scene early on Sunday to stop the flames spreading to nearby apartments.
Firefighters praised the staff and management at the club who quickly evacuated the building.
Nearby residents such as David Barrington could see the dramatic scenes from their city centre apartments.
The extent of the damage to the upper part of the building in Lower Severn Street can be clearly seen.
Some 25 firefighters remained at the scene on Sunday to damp down at the building.
Investigating officers will enter the building when it is deemed safe to try to discover the cause of the devastating fire.