Just a short way down are the piers where you can pick up a boat leading either up the Golden Horn or up the Bosporus.
I was traveling up the Golden Horn. Here’s what wiki says: “It is a scimitar-shaped estuary that joins the Bosporus just at the point where that strait enters the Sea of Marmara, thus forming a peninsula the tip of which is “Old Istanbul” (ancient Byzantium and Constantinople).”
These are some buildings along the way. I took the public ferry for about a dollar and it was great fun.