Zygor

Zygor is the home-planet of the Zygons. Zygor is known to be warmer then Earth and covered in water. This water is in the forms of lakes which have a different mineral composition. There are also no icecaps on the planet. Known native lifeforms of Zygor include the unaltered Skarasen and the Zygons. The whole planet was destroyed in the war against the Xaranti, though many Zygons were able to escape before the destruction. (DW: Terror of the Zygons)

A group of Zygons that crashlanded on Earth around 1909 tried to make Earth like Zygor. (DW: Sting of the Zygons


 * This could mean their war with the Xaranti that destroyed Zygor took place before 1909 or that the planets the Zygons conquered were always made to look like Zygor.