The Tower of Omens was a tower constructed to watch and be a base of re-entry from Dark Side.
To deal with the increased threat from the Lunataks, the ThunderCats along with the Berbils built the Tower of Omens. It was erected near the Forest of Mists, the only entrance to Dark Side that the ThunderCats could travel through safely. Bengali, Lynx-O, and Pumyra spent most of their time on Third Earth here, along with Snarfer. When the rest of the ThunderCats left for New Thundera, Tygra was left to maintain the Tower, while Pumyra was put in place over at Cats Lair on Third Earth.