The roman emperor Constantin the great divided the roman empire into two, one east here in Constantinople, and the old west with Rome in Italy as capital. Contanstinople lasted for 1123 years!!!
It was concered by the Turks in 1453. The city, since then called Istanbul, is still there, still magnificent today.
At the very centre was the pillar from which all road distances in the empire were measured.
And the pillar is still there, and the virtual cache is to find the pillar and to e-mail back the name of that pillar which is stated on a sign in front of it. The Topkapi dagger and famous market and Blue mosque 3 minutes away in each direction.
And while you are there, try to have time to visit the Basilica Cistern. It has been in many movies, ex Bond movie.
BR from gafs