Two prominent examples of Ancient Greek architecture is the Serpentine Column and the Leander’s Tower.
The Serpentine Column (or Yilanli Sütun as the locals call it) has the distinction of being Istanbul’s oldest remaining Greek monument. It’s close to 2,500 years old! The Column harks way back to 479 B.C. This was erected in Apollo’s honor after the triumph of the Greeks over the Persians at Plataea. The Greeks had to 
defend their empire from the attacks led by Xerxes I, the king of Persia and they succeeded. And this column is the symbol of their success and it commemorates the 31 Greek city-states that joined hands to bring about the victory. They melted the weapons of their enemies to erect the bronze column.
It originally stood at Delphi. When Istanbul (or Constantinople then) was proclaimed the new capital, Constantine I had it moved here in 324 B.C. From that time on, the Serpentine Column has stood at the Hippodrome at the Sultanahmet quarter.
The column is actually a sacrificial tripod for the ancient Greeks. It was made up of three serpents, with their bodies intertwined, forming a column that is 8 meters in height. Their heads reach the top of the column. These serpent heads supported a golden bowl. However, this bowl is believed to have been lost or stolen when the city was sacked during the Fourth Crusade. Also, the heads were broken sometime during the late 17th century. Some say that, on a whim, a drunken nobleman (a member of the Polish consulate) hit the heads. Some portions of the heads survived and are now placed at the Istanbul Archeology Museum.
Another important symbol in Istanbul is the Leander’s Tower, which is also called the Maiden’s Tower. Standing majestically on an islet along the Bosphorus Strait, it is a familiar and well-loved sight. This was built in 408 B.C. by Alcibiades, the Athenian General. This famous tower was erected with the purpose of keeping watch for Persian ships sailing along the Bosphorus. The tower underwent several reconstructions and expansions. These developments were spearheaded by the emperor Alexius Comnenus. For centuries, it has served the city of Istanbul well as a lighthouse. Now, you can also enjoy a leisurely meal as now it also has a café and restaurant.
The tower comes with an interesting legend. It is said that a sultan had it built to protect his daughter. You see, an oracle predicted that the sultan’s beloved daughter will die from a snake bite at her 18th birthday. The daughter lived there, away from any snakes that might bite. However, on the day of her birthday, her father brought her a basket of fruits as a gift. Alas, an asp was in the basket, among the exotic fruits. Out it came and it bit the daughter, exactly as the oracle had said. That’s why the tower is called the Maiden’s Tower.
Another story that relates to the tower is the tale of Hero and Leander. Leander falls in love with a priestess of Aphrodite, Hero. Leander would swim across the strait just to see her. With his words and arguments, he convinces Hero to let him make love to her. Their love affair continued until one fateful night, Leander failed to cross the strait – Hero’s light was blown out. Leander drowns and out of grief, Hero flings herself out into the sea. Hence the name, Leander’s Tower. The tower figured in the James Bond movie, “The World is Not Enough”.