Marina Bay Sands

To get a sense of just how fast Singapore - Asia's wealthiest country - is changing, head to the top of the Marina Bay Sands Hotel, opened in 2010, whose three 56-storey towers are connected across the top by an astonishing, 340m-long platform known as the Sky Park. If you're staying at the hotel, you can enjoy stunning views from the infinity pool, the highest of its type in the world. Otherwise, a cocktail at the bar may help you appreciate the scene below, which is even more breathtaking at night. Half of what you can see in every direction wasn't there five years ago, and construction cranes mark the locations of even newer projects that will sprout up this year or the next.

Once the saline estuary of the Singapore River - the city's mercantile focal point since 1819 - it was transformed into a freshwater reservoir by the Marina Barrage completed in 2008. The 350m dam is now a very popular venue for strolls and picnics.

The barrage was also designed to prevent flooding in low-lying areas. When there's very heavy rain (a frequent occurrence in Singapore) and the tide is low, crest gates open to allow rainwater to escape out to sea. When the tide is high, the dam remains shut, keeping out seawater. If necessary, giant pumps suck excess water out of the reservoir, keeping its level constant. Storm surges associated with rising sea levels are likely to pose a growing threat to coastal areas, and more countries are facing serious water shortages, in part because of climate change, so other cities may consider adopting - or adapting - some of the technologies on display here.