Mars

Mars is now a desolate and uninhabitable planet but it was not always this way.

Long ago it was inhabited by human refugees from Sirius until cosmic influences made it unhabitable.

Here is a quote from Contact Report 251 that mentions Mars:

Two large, genetically-manipulated peoples fled from the Sirius regions and settled in an area on the other side of the Sun. This meant they landed within, and then inhabited, a very distant part of a remote solar system; indeed, on planets beyond the galaxy's central sun, the sun of the Milky Way. Eventually, however, they were discovered by space travellers from the Old Lyrian lineage, whereupon they emigrated into the Lyra regions. Ultimately, within more recent terrestrial history, they came to our planet, where they settled in China, Japan and other locations, and various new, so-called races formed. Upon leaving the Sirius regions, the other genetically-manipulated peoples found a way to the SOL System, where several thousands of rebellious genetically-manipulated people had previously been banished to a myriad of terrestrial locations as a punishment. These masses of diverse races found refuge on the planets Mars and Malona/Phaeton, respectively, where they constructed cities, pyramids, stations and other things. They led a good life on Mars until the planet become uninhabitable through cosmic influences. For this reason, the genetically-manipulated people had to leave that planet in ancient times and, subsequently, they settled on Earth. Over the course of time, they became terrestrial human beings whose true and genuine Ur-origin was within the regions and planets of Sirius.