This seafood restaurant is all about ultramodern design, with sand beneath a Plexiglas floor, rusted-iron accents, huge fish-photo blowups, and a full wall of windows that look onto Ara Pacis. An outpost in famed chef Antonello Colonna's consulting empire, Reef produces Roman fare with a modern twist: try the spigola in crosta di arachidi (with a peanut crust). There's a sushi bar at the entrance, where you can sit and view the full workings of the kitchen through a glass wall.