Galleria Vittorio Emanuele II
The Galleria Vittorio Emanuele II is an extravagant 19th-century building that's now a shopping mall. Situated in the center of Milan, its glass top makes for a great viewing experience - visitors can walk a path on the rooftop for 360° views of Milan.
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I'd suggest finding a good cafe/ restaurant/ bar on level 3 or above around the square and taking in the views from their instead.
Ne vale la pena anche se il prezzo forse risulta eccessivo.