The paper by I. Antoniadis explores the possibility of a large internal dimension at energies of a few TeV, a prediction from perturbative string theories. This dimension is linked to the supersymmetry breaking scale. Despite initial concerns, this scenario is consistent with perturbative unification up to the Planck scale in a specific class of four-dimensional string models. The paper discusses the phenomenological implications, particularly the decompactification phenomenon and the pattern of supersymmetry breaking. It highlights that the extra dimension can lead to the repetition of states with the same quantum numbers, primarily affecting gauge particles and some matter fields. The paper also addresses the challenges and future directions, including the cosmological constant problem and the need for a more detailed analysis in realistic string models.The paper by I. Antoniadis explores the possibility of a large internal dimension at energies of a few TeV, a prediction from perturbative string theories. This dimension is linked to the supersymmetry breaking scale. Despite initial concerns, this scenario is consistent with perturbative unification up to the Planck scale in a specific class of four-dimensional string models. The paper discusses the phenomenological implications, particularly the decompactification phenomenon and the pattern of supersymmetry breaking. It highlights that the extra dimension can lead to the repetition of states with the same quantum numbers, primarily affecting gauge particles and some matter fields. The paper also addresses the challenges and future directions, including the cosmological constant problem and the need for a more detailed analysis in realistic string models.