Adventure seekers might want to check this cruise out: This summer, Clipper, a small-ship line that typically offers out-of-the-ordinary trips, is sailing the ultimate unusual itinerary. “Expedition to the High Arctic,” a one-time-only 16-day voyage on August 6, heads to some of that region’s furthest reaches. Geared to nature-lovers, passengers start off with a land-visit in Oslo before flying 400 miles to the first port of call -- Longyearbyen, where the Svalbard Archipelago is a highlight. Because of the unusual nature of the area, the cruise line says it’s not guaranteeing “ports of call” but passengers can expect to see plenty of polar bears, glaciers, and walrus, among other things. And not just from beyond the railing of cruise ship; the 122-passenger Clipper Adventurer is outfitted with a fleet of Zodiac landing craft and also staffed to the gills with naturalists and other regional experts who will lead passengers on educational hikes and other tours.