The term “milestone” often induces eye-rolling even when it’s equated with genuine achievement.

But it’s an expression that the Georgia Aquarium can safely use in connection with its fifth birthday.

Since opening its doors to great expectations on Nov. 23, 2005, the aquarium has watched more than 13 million visitors stroll its cavernous halls, getting a glimpse of rarely seen whale sharks, Beluga whales, manta rays and other aquatic animals.

A revamped Cold Water Quest Gallery opened in May, giving guests a closer experience with the African penguins and Southern sea otters who command the most attention in the exhibit.

Of course, the main reason for the redesign of Cold Water only a couple of years after the aquarium opened was to accommodate a much-publicized, $110 million dolphin exhibit.

That expanse, originally slated to open in time for the aquarium’s five-year celebration, will now open in 2011.

Here’s a look at some other aquarium stats:

500

Number of full and part-time employees who work at the Georgia Aquarium

13 million

Number of guests who have visited since 2005

$110 million

Cost of dolphin exhibit opening in 2011

$1 billion

Economic impact of the aquarium on the Atlanta and Georgia economies, according to Georgia State University studies

8 million

Number of gallons of water in the aquarium

2010

The year the aquarium was designated the world’s largest by Guinness World Records

300

Number of feathers a penguin can sport on every square inch of its body

6.3 million

Number of gallons of water in The Ocean Voyager exhibit

572,000 pounds

The amount of fish and seafood handled every year by the aquarium’s Husbandry Commissary

35 feet

The length a whale shark can achieve

400,000

Number of students who have attended educational sessions at the aquarium

28,000 pounds

Amount of fish consumed by Beluga whales per year

1.8 million

Pounds of sea salt used to make Ocean Voyager as salty as the ocean

61 miles

The length of the pipes that filter the water in Ocean Voyager

10,500 square feet

The size of the Aquatic Animal Health facility

Source: Georgia Aquarium

If you go

Georgia Aquarium

225 Baker St. NW, Atlanta

404-581-4000 or www.georgiaaquarium.com for ticket information.