While the peak foliage season is short, running from late September through October, there are no shortage of cruising options, with many of the major cruise lines featuring trips along the rivers at prices that will please. Highlights include the lively seaside city of Portland, Maine, sophisticated Halifax, picturesque Charlottetown, on Prince Edward Island, and enchanting Quebec City, an Old World-inspired gem whose historic city center is a UNESCO World Heritage Site. In Europe enjoy the Black Forest of Germany, the foothills of the Alps, and the tranquil Wachau Valley of Austria.