Where is the golden horn?
Solution 1:
The Golden Horn is the river that separates the top and bottom parts of Constantinople. You just need to parachute from the top of Galata Tower down south all the way to the river. Note you need to parachute into the river (ride it all the way in), don't drop from the parachute or it won't count.
You can see its name in the Database in the Locations section toward the end of the list.