You'll want to make a stop here because it is the best view of the city, with sweeping 360-degree panoramas. This fortress was built in the time of Alexander the Great and has seen the rise and fall of many empires.
We got a modern history lesson from our Armenian tour guide about the Armenian genocide in 1922. You can see the waterfront area that was burned down as thousands of Armenians were killed and forced to leave. Though Kemal Ataturk is revered here as the man who modernized Turkey, he and his Young Turks spurred the previously unknown enmity between Armenians and Turks that persists to this day.
If you're staying within a couple miles of the fortress, try walking down. You get to go through residential neighborhoods and meet people who don't often see tourists.