Incubation room

The incubation room was located in the Kaled Dome where the first Dalek mutants were grown.

Foreseeing a time when the Dalek Empire would become the dominant power of N-Space, the Time Lords sent the Fourth Doctor back to the waning days of the Thousand Year War to avert, or interfere with, the creation of the Daleks. The Doctor first attempted to have Davros deliver an incontrovertible order to have the Kaleds destroy the incubation room but was later forced to place explosives himself. When the time came though, he faltered when faced with the enormity of the task and his distaste for genocide. The Doctor was then approached by Gharman who told the Time Lord of an impending vote to stop the Dalek program only for Davros to maneuver around it. Unable to affect any more change, the Doctor made a last ditch effort to destroy the incubation room, the room being destroyed when an already active Dalek's casing completed the circuit. Despite this though, the Doctor despaired that, at best, he had only delayed Dalek evolution. (TV: Genesis of the Daleks)

In the centuries that followed, following the erection of the Dalek City, new Dalek embryos were grown in their city's incubation level. (AUDIO: Return to Skaro)

When on Moldox, the War Doctor destroyed an incubator aboard a Dalek flying saucer, cursing that if he had done that earlier, the Last Great Time War might have been avoided. The Eternity Circle later taunted him with this knowledge, though Cinder assured the Doctor of his morals. (PROSE: Engines of War)

When Davros was dying, he replayed security footage of the Fourth Doctor outside the incubation room to the Twelfth Doctor who angrily shut off the feed. (TV: The Magician's Apprentice)

Parallel universes
In the Warrior's universe, Sarah Jane Smith convinced the Doctor to destroy the incubation room. Before the Time Ring could be retrieved, Sarah and Harry Sullivan were exterminated by an already active prototype Dalek, which proceeded to fatally wound the Doctor. As the Time Lord was returned to Gallifrey, (AUDIO: Dust Devil) the Skarosian races discovered the Time Ring and, having proof of hostile alien life, unified as one force. Reverse engineering the Time Ring, the Skarosians became temporally active, reinforcing the moment outside the incubation room so as to prevent any further temporal incursions. (AUDIO: Aftershocks)