3 Best Sights in Istanbul, Turkey

This column stood at the center of what was a large circular marketplace or forum where Constantine formally rededicated the city on May 11, 330 AD. Carved out of blocks of a reddish-purple stone called porphyry that was especially prized by the ancient Romans, the column is 115 feet high and was once topped by a golden statue of Apollo, to which Constantine added his own head. Constantine was said to have placed various relics under the column, including an ax used by Noah to make the ark, a piece of the True Cross, and some of the leftover bread from the miracle of the loaves and fishes.

The major problem with the site of Byzantium was the lack of fresh water. So, for the city to grow, a great system of aqueducts and cisterns was built. Impeccably restored and opened to the public in 2018, the Theodosius Cistern dates from the 5th century to the reign of Theodosius II. A steep staircase leads you down into the cistern, where 32 marble columns support the Byzantine arches and domes overhead. The cistern occasionally hosts concerts and art exhibitions.

Fortified since Byzantine times, this little islet off the Asian shore guarded busy shipping lanes and has a restored, lighted, 18th-century tower that is now the star of the lower Bosphorus. Leander's Tower, as it was known in antiquity, ties the island to the legend of Leander, who was said to have swum the strait each night guided by the lamp of his lover, Hero—though this myth was, in fact, set in the Dardanelles to the southwest. The Turkish name "Maiden's Tower" comes from another legend, this one associated with several offshore castles. As the story goes, a princess was placed on an island to keep her safe after a prophecy foretold her death from a snakebite. Despite this precaution, she was bitten anyway, when a snake came ashore in a basket of fruit.