Daughter of the Gods
Baralda was a planet in the Third Galaxy, neighbouring the galaxy’s intellectual heart, Urbinia.
In an alternate timeline in which the First Doctor’s TARDIS landed on Urbinia instead of Kembel, the Daleks developed the Time Destructor. The Dalek Fleet attacked Baralda as a show of force prior to the Harvest of Urbinia. First Citizen Togrok sent a distress call to Chancellor Atrias on Urbinia but all the Baraldas were subsequently aged to death by the Time Destructor and the planet disintegrated in a matter of hours.
The Second Doctor later averted the timeline by averting the temporal collision which caused it. (Daughter of the Gods)