This may look like just another tourist spot, but Aquarium is just ripe for picking a fight. This combination of sea aquarium and botanical gardens is located right near the 54I black market zone of Singapore's Marina Gardens, so you know it's ripe for trouble.
The map provides a combination of indoor and outdoor locales, set up like a real aquarium, allowing plenty of opportunity to get in a good enclosed firefight while, at the same time, creating some good perching points for snipers. The map itself isn't as wide-spaced as others, but it does go a good distance from end to end, so you can get around the middle or try your luck in the outer walkways. Make use of the space and get those kills!