Here it is. The first, last and only home for the people of Cybertron. Massive caverns deep below the floor of the ocean have been built on by the remaining free Transformers. Buildings as different as can be shine like stars throughout the cavern. They serve as homes, storage units, meeting places and more besides are linked by streets made from scavenged materials liberated from the surface.
Transport tubes have also been set up than not only allow quicker movement from here to there but also serve the important purpose of taking those to the hidden airlocks to allow travel through the depths then surface of the seas and, from there, the wider world beyond.
Lights illuminate the homes, streets and tubes making the whole of Haven a sight to behold from any elevation, angle or perspective. Autobots, Decepticons and Neutrals living and fighting against the Quintesson threat. If only it could have been co-operation, not oppression, that could have brought all together as one.