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, others head for the nearby Seven Mile beach, and 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.

Just under a million passengers tramp though the cozy Alaskan capital every year. The docks are wedged in along the foot of Mount Roberts, and there are just a few streets for cruisers to explore, unless they’re signed up for an excursion to explore Mendenhall Glacier.

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.