Connected to the mainland by a causeway, Pigeon Island National Landmark, a 44-acre islet features remnants of an 18th century British naval garrison, a small museum, a beach and a trail that leads to a hilltop lookout. Dotted with the ruins of the officers’ kitchen and the curved roofs and old stones of the old powder magazines, the park enables visitors to sense a bit of the past. For a panoramic view, walk the gentle, half-mile hill to the top of Signal Peak. While the waters of Pocket Beach — a tiny spit of sand, opening to calm waters — are refreshing, the area is often crowded with cruise passengers.