Provincetown is the perfect launch point for whale-watching, since it's the closest port to Stellwagen Bank National Marine Sanctuary, the summer feeding ground for humpback whales. Some 17 species have been seen at one time or another; many of the estimated 350 remaining North Atlantic right whales, one of the world's most endangered whale species, frequent these waters. Take a whale-watching boat tour to scour the sanctuary waters for life.