Aside from having a meal and wandering the town, the only other activity in Anadolu Kavağı is to hike up to Yoros Castle, on the hilltop above town. While this run-down castle ruin hardly reflects the glory of its past, it does afford fine views over the Bosphorus and to the Black Sea. You can combine a castle hike with your lunch (though we'd rather bring up a picnic from the grocery store in town than eat at one of the restaurants on the hillside below the castle). Public WCs are also en route. You'll also notice lots of litter, as well as friendly but hungry stray dogs eyeing you, hoping
for your leftovers.
The moderately strenuous hike takes about 20 minutes each way. Most of the way up, you'll be passing through a military-controlled zone, so put your camera away. Once at the castle, feel free to take photos. Our hike goes up the south side of the hill where there's little breeze, so it may feel a little warmer than you'd expect.

Castle Hike:

Standing with your back to the ferry port, walk straight ahead toward the large, square street fountain (with the gold Arabic script). After the fountain, take the street to your left, and walk about 100 yards (bearing left at the fork) until you reach the corner of the yellow, 16th-century Ali Reis Mosque (you'll see a sign to Yoros Kalesi—that's Yoros Castle—across the street). Turn right and walk with the mosque on your right-hand side. Soon you'll see the Navy station fence on your left. After about 100 yards, you'll come to a fork—keep to the left.
Now the road gets steeper as you continue up and up, jogging right with the road. After passing a stand of cypress trees, the road makes a sharp curve to the left, giving you some glances of the Bosphorus beyond the parking lot. Up ahead, you also see part of the lower wall of Yoros Castle. Keep walking.
Past the wall fragments, there's another fork: The left fork goes to a military checkpoint, but you'll head right. Less than 100 yards later, after the road curves left, you'll see a large aerial photo of the castle on the wall to your left (with a sign reading To Castle/ Ceneviz Kalesi). Follow the steps next to the sign, up past the cafe tables. Keep to the right as the path, punctuated with simple steps, leads you through more humble eateries on its way to the castle entrance. You will soon see the castle wall to your left, as well as public WCs, picnic tables, and hammocks.
Reaching the end of the path, take the stairs to your left, through Yoros Cafe (ignore the plaster lion statues and menus— the steps are public, not part of the restaurant). These steps lead all the way up, straight to the gate of Yoros Castle. As you come through the gate (free, always open), you're in a wide-open courtyard with several rough paths and the graffiti-marred remains of the former military fortress. Head up to the top of the courtyard for your reward: spectacular views of the Bosphorus and the Black Sea—and the cool northerly breeze. Yoros Castle is quite popular on weekends in good weather, when it's packed with locals.  (s3)