Saying this is possibly the nicest bar experience I've ever had would sound like an statement difficult to qualify. I'm not really one that frequents bars too often (other than when I'm dragged there by a few enthusiastic friends), but for a cool evening walking along the ponte de Dom Luis promenade around midnight, the enigmatic vocals of middle-aged Portuguese crooner filled the air near the base of the bridge. Traversing around opened into a little platform nestled under the bridge, along the water, in front of the live singer. The wait staff brought me a blanket to shield from the cold, some port (because that's what happens in Porto) and a simple dessert I don't remember too well.
What I do remember is the atmosphere, the clear sky, the illuminating bridge reflecting off the river surface and the warm singing that accompanied.