The Stadium of Philippopolis is a 2nd-century Roman athletics track — 240 metres long, designed for foot races, chariot races, and athletic competitions — buried under what is now the main pedestrian thoroughfare of Plovdiv. The excavated northern end (sphendone) can be visited from a dedicated underground entrance in the pedestrian zone.
Descending into the sphendone is a genuine time-warp: you step from a modern shopping street into a Roman curved end-tribune with marble seating tiers, column bases, and carved decorative elements. The scale gives some sense of how large the complete stadium was. The rest of the track — running the full length of Knyaz Alexander I Street above — is inaccessible but is marked on the pavement.