Nice short video showing the relatively new (11 years old) Singapore Science Centre. Apparently they moved many exhibits from the National Museum, leaving the Science Center with over 1000 exhibits. Unfortunately I never had a chance to visit it, but it looks very interesting indeed.
I really like this video series from FocusSingapore. This particular clip showcases the 35-year old Singapore Zoo with its 315 animal species, and the largest captive orangutan colony in the world.
I visited the Underwater World on Sentosa Island, Singapore several years ago, and it is a wonderful idea and construction, walking underneath and around all the marine life. Over 2500 creatures and 250 species is an incredible variety of sea animals. Definitely worth a visit if you're there!
These two videos (parts 1 and 2) describe Singapore's famous Night Safari in good detail, including the more than one thousand animals within the zoo area. I was there in 2002, and while I didn't see all the animals shown in the video, is is truly an incredible experience to see the creatures when they're most active - at night. Definitely my personal highlight of Singapore!
Here's a brief video describing Singapore's famous Sentosa Island. For such a small island (5 square kilometres), there is an awful lot to do, from exploring the giant Merlion to exploring the Butterfly Park to walking underneath the Underwater World. When I was there a few years ago, one of my higlights was the Dolphin Lagoon!
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