It is proved that the isometry classes of pointed connected complete Riemannian n-manifolds form a Polish space, M ∞ * (n), with the topology described by the C ∞ convergence of manifolds. This space has a canonical partition into sets defined by varying the distinguished point into each manifold. The locally non-periodic manifolds define an open dense subspace M ∞ * ,lnp (n) ⊂ M ∞ * (n), which becomes a C ∞ foliated space with the restriction of the canonical partition. Its leaves without holonomy form the subspaceby the non-periodic manifolds. Moreover the leaves have a natural Riemannian structure so that M ∞ * ,lnp (n) becomes a Riemannian foliated space, which is universal among all sequential Riemannian foliated spaces satisfying certain property called covering-determination. M ∞ * ,lnp (n) is used to characterize the realization of complete connected Riemannian manifolds as dense leaves of covering-determined compact sequential Riemannian foliated spaces. Contents 1. Introduction 1 2. Preliminaries 3 2.1. Foliated spaces 3 2.2. Riemannian geometry 5 3. Quasi-isometries 6 4. Partial quasi-isometries 11 5. The C ∞ topology on M * (n) 12 6. Convergence in the C ∞ topology 13 7. M ∞ * (n) is Polish 15 8. Some basic properties of M ∞ * ,lnp (n) 17 9. Canonical bundles over M ∞ * ,lnp (n) 20 10. Center of mass 24 11. Foliated structure of M ∞ * ,lnp (n) 25 12. Saturated subspaces of M ∞ * ,lnp (n) 29 Acknowledgements 30 References 30 Key words and phrases. C ∞ convergence of Riemannian manifolds; locally non-periodic Riemannian manifolds; Riemannian foliated space. 1 Definition 1.1 (See e.g. [33, Chapter 10, Section 3Here, a domain in M is a connected C ∞ submanifold, possibly with boundary, of the same dimension as M .It is admitted that C ∞ convergence defines a topology on M * (n) [32]. However we are not aware of any proof in the literature showing that it satisfies the conditions to describe a topology [28], [17] (see also [26] and [27] if C ∞ convergence were defined with nets or filters). This is only proved on subspaces defined by manifolds of equi-bounded geometry, where the C ∞ convergence coincides with convergence in M * [29] (see also [33, Chapter 10]). The first main theorem of the paper is the following.Recall that a space is called Polish if it is separable and completely metrizable. The topology given by Theorem 1.2 will be called the C ∞ topology on M * (n), and the corresponding space is denoted by M ∞ * (n). For each complete connected Riemannian n-manifold M , there is a canonical continuous map ι : M → M ∞ * (n) given by ι(x) = [M, x], which induces a continuous injective map ῑ : Iso(M )\M → M ∞ * (n), where Iso(M ) denotes the isometry group of M . The more explicit notation ι M and ῑM may be also used. The images of the maps ι M form a natural partition of M ∞ * (n), denoted by F * (n). A Riemannian manifold, M , is said to be non-periodic if Iso(M ) = {id M }, and is said to be locally non-periodic if each point x ∈ M has a neighborhood U x such thatLet M * ,np (n) and M * ,lnp (n) be ...