Exploring Greece’s Mt. Athos peninsula—where medieval monasteries pepper the forested slopes—is near-impossible alone, with many areas off-limits to visitors. This full-day cruise trip from Thessaloniki makes it possible, with the benefit of added commentary. Admire the scenery and sail by the still-working monasteries as you learn detail about them you’d probably otherwise miss. Plus, visit a nearby seaside town and enjoy traditional Greek entertainment as you sail back.