  We study the level lines of GFF starting from interior points. We show that
the level line of GFF starting from an interior point turns out to be a
sequence of level loops. The sequence of level loops satisfies
"target-independent" property. All sequences of level loops starting from
interior points give a tree-structure of the plane. We also introduce the
continuum exploration process of GFF starting from interior. The continuum
exploration process of whole-plane GFF satisfies "reversibility".
