For this one you want to head over to the 'Fresco
' section in the middle-right part of the map
. There you will see a tall tower that is reminiscent of the Leaning Tower of Pisa. Go to this tower, once you are there climb ALMOST
to the top. Pay attention to where the studs stop appearing along the outer railing near the ceiling of the building.
From there just carefully jump on said outer railing and slide all the way down.
Video for visual reference: