🇬🇷 Greece · Hydraulic works
Tunnel of Eupalinos (Efpalinos) — Samos Aqueduct
Archaic (600–500 BCE) · Ionian Greek (Samian) — engineer Eupalinos of Megara
Herodotean 1,036-m tunnel 550 BCE dug from both ends with 60 cm meet error.
🇺🇦 Ukraine · Submerged site
Olbia Pontica – Submerged Lower Town
Archaic to Medieval (646 BCE – 4th c. CE; revisited 14th c.) · Milesian Greek / Scythian / Roman / Gothic
Milesian Black Sea emporium whose harbour lower town now lies 1–4 m under Bug–Dnieper liman.