Rifts

Rifts conceal pieces of Subject 16's Cluster puzzles in Assassin's Creed: Brotherhood, and are the equivalent of Glyphs from Assassin's Creed II.

Locations
Colosseo

At the very top, northern side of the Colosseo, just west of the View Point.

Rosa in Fiore

On the north wall of the brothel, on the second floor wall.

Pantheon

Inside the Pantheon, on the wall right above the main entrance.

Barracks

East side of the wall, outside the palazzo.