The largest unpopulated wilderness in all of Italy, Val Grande is located about an hour's drive northwest of Milan on A8. For those who like their landscapes all rocky peaks and wuthering heights, as you'd assume would be the case with the Alps, the hiking trails are many and varied in difficulty and length, some taking a few days time if you're willing to camp overnight.
There are a few visitors centers in the park where you'll be able to obtain maps or even book guides, since it is recommended for those hiking the area for the first time to do so (no need to make this your last adventure due to getting lost). The vistas range from grassy meadows to meandering streams and breathtaking mountain panoramas, made all the better by the great proximity to Milan. Some recommended treks include that up Mount Vada, those over the pasture-lands of Ossola or the trip up Mount Faie, which is located near the tiny village of Rovegro.
For much more information on topography, accommodations, and potential hiking routes, access the official website.