Dalazar

Dalazar was both a continent on Skaro and the name of its capital city. It was the original home of the humanoid Daleks, and thus the point of origin of their successors, the more familiar cyborg Daleks. It was separated from the continent of the Thals, Davius, by the Ocean of Ooze. (TV21: Genesis of Evil)

The continent
Dalazar was the location of the Radiation Range, a mountain range where the humanoid Daleks discovered pure cobalt.

The continent also had a region named Darren which was the home of the Dalek War Council. There, the humanoid Daleks labored to create powerful neutron bombs, with which they hoped to end their war with the Thals. War minister Zolfian was known to frequent this area to supervise the project. Concomitantly, Zofian and his chief scientist, Yarvelling, were also mass-producing robotic warriors which would seek out and kill any Thals which happened to survive the bomb. These robots had the same recognizable design of the cyborg Daleks.

The continent was laid waste, however, when it was bombarded by meteorites that set off the neutron bomb in Darren.

The city
For two years, Yarvelling and Zolfian waited in the bunker underneath the factories at Darren for the radiation levels to drop. Guessing as to the relative safety of the surface, the duo emerged and made their way overland to the city of Dalazar. There, they discovered that the capital itself was in ruins.

Despite the massive damage that had been done to Dalek culture, Zolfian charged Yarvelling with somehow raising an army to continue the war with the Thals. As they wandered the ruins of Dalazar, they were surprised by the first sign of life they had seen on the entire continent: one of the robots they had been building two years before.

It explained that it was no longer simply a robot, but a fusion of one of the humanoid Daleks in Darren with its robotic interior. It was a cyborg. And it commanded Yarvelling to figure out a way to replicate the process by which it had become joined so that an army of cyborg Daleks could be created.

Yarvelling agreed, even as it was clear that he was dying of radiation sickness.

In the ruins of the city of Dalazar, on the continent of Dalazar, the first tentative steps towards a new Dalek Empire had been taken.

"New Dalazar"
After the secret of Dalek self-replication had been learned, an army of Daleks recreated Dalazar into the new Dalek City. This un-named city had the ability to attract the post-nuclear "magnetic sand" of the surrounding desert. It could therefore build a temporary shield around itself. (TV21: Genesis of Evil)

It was from this city that the Daleks tested their first spacecraft and began their conquest of other worlds. (TV21: The Amaryll Challenge)

The city was all but destroyed by the Monstrons, who attacked when the Daleks were busy fighting a rust plague that threatened to infect all Daleks. (TV21: Plague of Death, The Menace of the Monstrons) However, it was rebuilt in a matter of months. (TV21: Eve of War)

Behind the scenes
Dalazar has never been referred to, nor explicitly ruled out of existence, by any other Dalek story. While its importance to the creation of the Daleks would seem to be contradicted by stories like Genesis of the Daleks, its existence is made possible by the scant reference televised Doctor Who has made to the geography of Skaro.

The question of whether "New Dalazar" is actually the same city depicted in DW: The Daleks is an open one. Certainly the drawing of the city gives some credence to that possibility, as does the city's use of electro-magnetism.