Good luck finding a bottle of this in a store, but you may be able to hunt it down online. I imagine it's easier to find in Europe, but in the US it's a challenge, rubes that we are. The irony is that Aqua Classica smells very conservatively American in a "guy's aftershave" sort of way, but with a little twist. The structure is one we've all smelled a million times, several citrus fruits (lemon, bergamot, lime) layered upon a biting wood note (oak) with a pinch of spice (ginger), but woven into the mix are a couple of high-end "green" aroma chemicals, materials that enhance the sparkling fruits while also lending the woody spice some depth and finesse. The result is something to be worn when dressing to impress. You want to reach for this before a hot date to a classy Italian restaurant, or cruising the beaches for friendly platinum blondes.
Besides the fact that it's obviously been modernized at some stage of its one hundred year lifespan, Aqua Classica fascinates me. Actually, all of these eau de cologne frags fascinate me. They're all the same, sometimes nearly identical, yet somehow always different. I've realized in my years of wearing these things that the division between white collar and blue collar typically comes with the addition of two or three top-shelf "fresh" synthetics, mostly used as depth and texture enhancers. Acqua di Parma uses a pleasant musk note to extend the drydown, and Royal Water emits a crisp juniper berry that quashes its competition. Aqua Classica simply smells abstractly green in a way that balances the serene fidelity of its naturals. Bear in mind that f you already own AdP or RW, Acqua Classica would be unnecessary for you.
Unsurprisingly, the downsides are its feeble strength and longevity. Though it's impressive for this style, AC will really only command a presence for two or three hours, and gently at that. Then there's the extra cost of the stuff - it ain't cheap. Unless you're independently wealthy, I'd recommend (a) owning just one of these expensive EDCs, or (b) spending twenty bucks on twenty seven ounces of the equally charming 4711 and calling it a day.