Singapore's SEA (Southeast Asia) Aquarium holds the title of the largest aquarium in the world. It has over 12 million gallons of water and more than 800 species, with nearly 100,000 aquatic inhabitants in total. Less than a year old, the SEA is part of Singapore's Resort World Sentosa complex. Because of its size, this is certainly a daylong attraction, but if we had to name one single headlining feature, it would have to be the single-pane viewing panel on the aquarium’s “Open Ocean” exhibit. This window stands nearly 120 feet wide and 27 feet tall, making it the largest single-pane aquarium window in the world.