View Point

From Assassin's Creed Wiki

View Points are high structures that over look the surrounding terrain. When acquired they uncover a portion of your map and show points of interest; for instance someone to eavesdrop on to continue the game. They can be found by accessing your map, depicted by tiny eagle icons, as well as an eagle soaring around the structure itself.

These high points give the player the ability to find interrogation, eavesdropping, pickpocketing, informative and even assassin's targets' locations.

You can also find civilians to save, increasing your chances to complete all of the side quests, and unlocking the moving hiding spots (Scholars, Vigilantes) in each portion of the city.

At the bottom of each is always a conveniently placed pile of hay, allowing you to do a leap of faith to get down.