In this paper we construct for every integer n > 1 a complex manifold of dimension n which is exhausted by an increasing sequence of biholomorphic images of C n (i.e., a long C n ), but it does not admit any nonconstant holomorphic or plurisubharmonic functions (see Theorem 1.1). Furthermore, we introduce new holomorphic invariants of a complex manifold X, the stable core and the strongly stable core, that are based on the long term behavior of hulls of compact sets with respect to an exhaustion of X. We show that every compact polynomially convex set B ⊂ C n such that B =B is the strongly stable core of a long C n ; in particular, holomorphically nonequivalent sets give rise to nonequivalent long C n 's (see Theorems 1.2 and 1.6 (a)). Furthermore, for every open set U ⊂ C n there exists a long C n whose stable core is dense in U (see Theorem 1.6 (b)). It follows that for any n > 1 there is a continuum of pairwise nonequivalent long C n 's with no nonconstant plurisubharmonic functions and no nontrivial holomorphic automorphisms. These results answer several long standing open problems.