Just behind the Philadelphia Museum of Art is a charming line of miniature classical facades marking the country’s first municipal water-delivery system, a 200-year-old installation that has been cleverly restored as an elegant river-top restaurant. 

Unfortunately, the lovely period rooms are reserved for the banqueting crowd (this is a popular local wedding reception spot), but the high leather banquettes in the restaurant section are nice enough—though I'd aim for a table for two by the windows with a river view. Even better, in fine weather there is al fresco dining on the terrace. Service  can be slow, and it can vary visit to visit, from lovely and solicitous to frankly brusque (especially if there's a wedding or other large party in the house). But the location is hard to beat. Try the lobster ravioli, free-range chicken, or an Angus steak off the grill, and wash it down with a bottle from the "water list"—like a wine list only, you know, more cheekily in keeping with the location.

Speaking of which, take the time to check out the adjacent (and free!) Water Works Interpretive Center, which aims to teach the importance of clean water via high-tech exhibits—a simulated helicopter ride takes visitors from the Delaware Bay to the headwaters of the Schuylkill River—and offers an engaging message of environmental awareness.