Ynes-Mons is the name of the town. It has a wonder called the 'isle of darkness' which is kinda the opposite of what it does. If a general spends 4 seasons in that town they will gain enlightenment and an attribute called................... yep 'isle of darkness'. The trait gives a +2 to influence.

The town also already has the highest level of school so while you are there you gain some nice traits and usually a heap of cool retainers like druidic surgeons, natural philosophers, geographers etc.

If u are playing as Casse or conquer the town as someone else, make sure u send ALL generals there for the training. The longer u leave them there the more cool crap they get.