Astral-sea

The Astral-sea is the largest within the Dreamscape and the Planes of existence within Hir. The Astral-sea is the plane of consciousness and it is most often entered through astral projection, a process of sending your mind into the plane rather than your physical body. However, it is possible although difficult to enter physically, often requiring immense training and experience to achieve. The difference between entering physically and mentally is one of survival. Entering mentally makes defence from astral creatures incredibly difficult as attacks and magic from a projected individual are not as strong. Entering physically allows the inhabitant to utilise their full capabilities. 
Study of the Astral-plane is well documented but it is still mostly unexplored, this is due to the Astral-sea being one of the many reasons for magic's exitance and the ability to influence other individuals' minds.