Glacier Bay National Park is an incredible park in Alaska. It consist in a long fjord surrounded by majestic mountain peak and massive glacier that end up in the ocean. The most famous glacier is the Margerie Glacier a the far end of the fjord, it is huge and still very active. It is quite a sight to see the enormous wall of ice calve and break. The noise of the ice breaking is breathtaking. Often it is possible to see big iceberg floating near the glacier.
The park can only be visited by boat or seaplane. Only 2 cruise-ships per day are allowed in the park, If you are planning of taking an Alaska Cruise make sure that the itinerary includes Glacier Bay National Park. Here are more information about cruising in Glacier Bay national Park.
For more information regarding the park, maps and hours of operation this is the link.