The City Center Tram is awesome, especially if you are staying in one of the hotels that the tram stops at (Monte Carlo, Aria, Vdara, Bellagio). It's a very convenient way to get around to the different hotels/casinos/stores. The tram was clean, although one trip, it smelt like urine. Not sure if the inside itself smelt like urine, or someone else in there did. Meh.. But other than that, it usually smells like Crystals. I think it's the Aria scent.