Come for the history, stay for the views. Signal Hill National Historic Site is St. John's most visible and visit-worthy attraction. The rugged, barren hill is the city's preeminent landmark, rising above the entrance to the harbor and topped with a craggy "castle" complete with a flag fluttering overhead -- the "signal" referred to in the name. Over the centuries a succession of forts have occupied this hill (as did three different hospitals). The current, castlelike structure, officially called Cabot Tower, dates from 1897. But the hill really secured its spot in history in 1901, when the Italian inventor Guglielmo Marconi received the first transatlantic wireless telegraph broadcast -- three dots, the letter S in Morse code, sent from England -- on an antenna raised 121m (400 ft.) on a kite in powerful winds. Start in the interpretive center, where you get a briefing about the hill's history. (Military drills and cannon firings still sometimes take place in the field next to the center; ask here if you're interested.) From the center, follow serpentine trails uphill to the tower, where you're rewarded with breathtaking views of The Narrows and the open ocean beyond it. You'll even sometimes spy icebergs floating by in early summer, and you can see whales most anytime of year -- talk about getting your money's worth from one stop! Interpretive placards, scattered about the summit, feature photographs from various periods in the city's history. Bring the kids; this is almost a must-do.