An oasis amid the roaring hustle of Piraeus port, Kastella Hill is a patchwork of modern apartments and pastel-hued townhouses. At the hill’s summit, the church of Profitis Ilias and open-air Veakio amphitheater (a lovely venue for summer concerts) have dazzling sea views, the Saronic islands twinkling on the horizon. Stroll down to Mikrolimano, the ‘little harbor’ lined with fishing boats, ritzy yachts and fancy seafood restaurants—perfect for a lazy lunch or starlit dinner.