This is what’s left of the Column of Arcadius. It is not much of a sight, but well: erected in 402 by Emperor Arcadius it was decorated with bands of sculpture representing the triumphs of the emperor, like the Trajan Column in Rome. It stood at the center of a forum and was over 50 meters high, topped by a Corinthian capital surmounted by an equestrian statue of Arcadius, placed there by his son, Theodosius II, During an earthquake in 704 it came down.
On You Tube I found a fascinating movie where someone climbs the (still intact and in good repair) staircase that spirals up.