The Obelisk of Theodosius has been standing here for 1,600 years, yet when Emperor Theodosius erected it in 390 AD, it was already ancient: carved for Pharaoh Thutmosis III around 1500 BC and hauled, all 70 tonnes of it, from Egypt to Constantinople by ship. The hieroglyphs on its four granite faces still celebrate a pharaoh's victories. The holes peppering the stone once held bronze sheets that flashed in the sun.

Stand at the base and peer into the excavation pit beside it. The ground has risen so dramatically since the 4th century that what was street level is now metres underground. Istanbul is a cake of civilisations, each layer burying the last.

VoiceMap's self-guided audio tours use the obelisk to trace the Hippodrome's full arc, from Roman chariot races through Byzantine ceremony to Ottoman repurposing, placing one monument at the centre of three empires.