where in florence is the Mercato Vecchio building?
I had trouble finding this one too. what you have to do is: go to Florence, the Santa Maria Novella district. This is the district the farthest west, or the left side of the city looking at the map. There is a rounded part on the dividing line. In the lower right hand "corner" of this district. Straight above that is a semi square looking building on the map. It is actually a courtyard. Make sure your notoriety is down and switch to eagle vision. The glyph is near the northeast corner of this courtyard/building. Climb up on the outer "walls" of this court and head for that corner, Its on the side of a window addition on the building, the glyph is like chinese writing going up and down. Good luck!