Second, for the case of 2 extra dimensions, the gravitational force law should change from on distances ~ 100µm-1 mm, and this deviation could be observed in the next few years by the new experiments measuring gravity at sub-millimeter distances [11]. Third, since the SM fields are only localized within in the extra n dimensions, in sufficiently hard collisions of energy , they can acquire momentum in the extra dimensions and escape from our 4-d world, carrying away energy*. In fact, for energies above the threshold , escape into the extra dimensions is enormously favored by phase space. This implies a sharp upper limit to the transverse momentum which can be seen in 4 dimensions at , which may be seen at the LHC or NLC if the beam energies are high enough to yield collisions with c.o.m. energies greater than . Notice that while energy can be lost into the extra dimensions, electric charge (or any other unbroken gauge charge) can not be lost. This is because the massless photon is localized in our Universe and an isolated charge can not exist in the region where electric field can not penetrate, so charges can not freely escape into the bulk. In light of this fact, let us examine the fate of a charged particle kicked into the extra dimensions in more detail. On very general grounds (which we will discuss in more detail in section 3), the photon (or any other massless gauge field) can be localized in our Universe, provided it can only propagate in the bulk in the form of a massive state with mass ~ , setting the penetration depth of the electric flux lines into the extra dimensions. In order for the localized photon to be massless it is necessary that the gauge symmetry be unbroken at least within a distance >> from our four-dimensional surface (otherwise the photon will get mass through the "charge screening", see section 3). As long as this condition is satisfied, the four-dimensional observer will see an unbroken gauge symmetry with the right 4-d Coulomb law. Now, consider a particle with nonzero charge (or any other unbroken gauge quantum number) kicked into the extra dimensions. Due to the conservation of flux, an electric flux tube of the width must be stretched between the escaping particle and our Universe. Such a string has a tension per unit length. Depending on the energy available in the collision, the charged particle will be either be pulled back to our Universe, or the flux tube will break into pieces with opposite charges at their ends. In either case, charge is conserved in the 4-dimensional world, although energy may be lost in the form of neutral particles propagating in the bulk. Similar conclusions can be reached by considering a soft photon emission process [8]. Once the particles escape into the extra dimensions, they may or may not return to the 4-dimensional world, depending on the shape and/or the topology of the n dimensional compact manifold . In the most interesting case, the particles orbit around the extra dimensions, periodically returning, colliding with and depositing energy to our 4 dimensional space with frequency Hz. This will lead to continuous "fireworks", which in the case of n = 2 can give rise to ~ mm displaced vertices.