On February 2014 CNN listed the Europe's 12 most impressive metro stations, and Toledo in Naples is considered the first one of this interesting list:
CNN 2014/02/04: Toledo is Europe's best metro station
The Telegraph
Opened in 2012, Toledo station defies its depth -- at 50 meters, one of the deepest in Naples -- with a design based around themes of light and water.
A work called "Light Panels" by Robert Wilson illuminates the station corridor furthest underground.
This stunning station has competition: it's part of the city's network of so-called Metro Art Stations.
You need to search while a lot of muggles are around you, maybe you need to wait for a while because stealth is required!
Please avoid to search it if policeman is watching at you!
Bring your own pen to sign the logbook.
Notes:
-you can access the cache only when metro station is open, not during the night
-start your GPSr in advance, as GPS signal is not so good and slow to lock; at very end signal will be lost...