
In winter, predictably, Seward is a veritable ghost town—and that's just how the 3,000 or so year-round locals like it. But come summer, tourists attack this end-of-the-road Alaskan fishing village at the tip of the Kenai Peninsula like an orca in a feeding frenzy. Those who don't arrive aboard hulking cruise ships descend in rental cars from Anchorage or by train via the Alaskan Railroad; most spend several days in the area. The population swells exponentially in the summer, and if you happen to be here over Fourth of July—when the town holds its annual Mt. Marathon foot race—you'll be among 30,000 others splashing around for space in Seward's colorful downtown.

The Venezia Terminal Passeggeri might have a romantic ring to it, but there's absolutely nothing quaint about this sprawling cruise terminal that is so vast it's often used to host trade fairs. Sure, Venice will always be stunning. But during the summer months, forget finding a serene trattoria for a spot of gelato or floating romantically down a canal with your beloved. It's all tourists, all the time—making the population of authentic Venetians seem just as endangered by the human tourist flood as the city is by rising sea levels.

Throughout the year, behemoth cruise boats from San Diego and Los Angeles lumber down to Cabo San Lucas, the main port of call for Sea of Cortez and Mexican Riviera itineraries. Whale watching during the winter season pairs with the high season of spring and summer to make for paradise lost, pretty much year-round. As you wait to be cattle-called into port aboard inflatable tender boats, here's what you'll have to look forward to: retail madness in the wall-to-wall duty free shops, Coyote Ugly-style bars with Americans behaving badly and Mexican food that's far from authentic.

Its proximity to the remarkable Roman ruins at Ephesus make Kusadasi, on the Aegean Sea along Turkey's east coast, a popular port of call for most Eastern Mediterranean cruises. But summertime's intense heat and the relentless cruise ship arrivals mix up a volatile cocktail. Overcrowding and heat-induced short tempers from shopkeepers who take bartering a little too seriously turn the otherwise idyllic destination into some sort of inferno. The good news? Cruise ships arrive in Kusadasi year-round: Come during spring, fall or winter when it's far more pleasant.

Almost all of the major cruise ships docking in nearby Naples talk their passengers into day-trip excursions to the magical isle of Capri and its postcard perfect Blue Lagoon. But finding breathing room to enjoy the island's natural beauty during the region's prime European and American tourist season (April to October ) is a long shot. Capri is scarcely four miles long and not even half as wide. And thousands of tourists arriving daily via hydrofoils from Sorrento and Naples and smaller cruise ships already docked at Marina Grande give little space for real serenity.

The 2.4 million cruise passengers who visit Cozumel every year pull up to one of three docks around tourist hub San Miguel. No longer the appealing, if gritty, Mexican outpost it was just a decade ago, this island port is packed with six to 10 ships on most winter days. Passengers shuffle between suburban mall-style shops and hit the beer joints, unless they’re heading for the island’s beaches or the Mayan ruins on the mainland.

Six or seven megaships bobbing offshore is business as usual during high season at Cayman's capital, George Town. Tender boats shuttle the masses—1.8 million a year—back and forth to the island, where some hit the brand-name shops in town while others head for the nearby Seven Mile Beach. Still more hop on buses bound for diving trips or jaunts that range from snorkeling to feeding the rays at Stingray City.

The 1.7 million cruise passengers who come here every year do so via giant white ships, often six to eight at a time during the winter months. Traffic jams into the main town of Charlotte Amalie, just a few miles from the ships, are commonplace. Considering the time and hassle it takes to get to nearby beaches like Megans Bay or Coki, you may not want to leave the ship.

Ditto the numbers and scene in St. Thomas here: It’s the same story in Nassau. Rivers of passengers flow onto Bay Street, the main shopping drag, and invariably file into the seriously mobbed straw market. Claustrophobes, be warned.

According to research consultant G.P. Wild International, about 1.2 million cruisers pour into Phillipsburg annually. During the prime winter months, traffic jams, packed shopping strips and wall-to-wall beach towels at Great Bay Beach in town are par for the course.

Another marquee port on the Inside Passage Alaska run. When thousands of passengers are in port for the day in tiny Ketchikan, it can feel like a gold rush stampede. Many are beelining it to the t-shirt and souvenir emporia located close by the docks.

These two Greek isles are in the same boat. Beautiful islands both, but four or five (or more) jumbo ships anchored offshore during the July and August crush might leave you gasping for the wrong reasons. Getting that classic photo of a white washed blue-domed chapel might be a long shot, unless you don't mind your fellow shipmates sharing the field of vision.

Few cruise ports are as picture perfect as Dubrovnik's Old Town. But when there are a gazillion tourists elbowing their way around the medieval ramparts that encircle the ancient city, you can end up feeling rather compressed yourself.

The giant Colossus of Rhodes, which once towered over Mandraki Harbor in Rhodes Town, would be shocked to see the imposing mega-ships that now fill the bay. The city's Old Town sure is a perennial charmer and the 700-year-old hilltop Acropolis at Lindos is stunning, but these two top sights are a madhouse during high season when thousands of cruisers descend on the island.