There are places on this Earth where you simply stand, slack-jawed, and pinch yourself to make sure you're not dreaming – and Singapore's Gardens by the Bay is as surreal a place as I've ever been. This billion-dollar techno-garden theme park is absolutely stunning right through, but the two stand-out highlights are its signature Supertree Grove – a collection of giant cyborg trees – and the Cloud Forest – a gigantic bio-dome that recreates the environment and climate of a mountaintop forest at sea level. As a bonus, there's also the world's tallest indoor waterfall.

The jewel in Singapore's crown is its Marina Bay precinct, with stunning views in every direction. There's the Durian-shaped Esplanade theaters, the imposing shard-shaped skyscrapers of the financial district, the shell-shaped ArtScience museum, and dominating the landscape, the bizarre, colossal Marina Bay Sands hotel complex itself – shaped like a giant cruise ship beached atop three giant columns.

And since 2012, in behind the Marina Bay Sands hotel, there's also the Gardens by the Bay, a billion-dollar work of art inspired and enhanced by nature, parts of which feel like you've stepped into a sci-fi movie.

Supertree Grove

Entering the Gardens, you're immediately introduced to one of the main attractions: the Supertrees. Standing between 25 and 50 m tall (80-160 ft), each Supertree is a vertical garden supporting a range of ferns, vines, orchids and other plants, which creep over the towering, purple skeletal structures.

Each Supertree is designed to mimic the function of a real tree, with photovoltaic cells to echo photosynthesis and contribute energy to run the park. The trees also collect water during Singapore's frequent heavy rains and channel it throughout the park wherever irrigation or fountains are needed. Some are also used as exhaust flues for the Gardens' underground biomass boilers.

For SG$5 (US$4) you can take an elevator up to a short skywalk between two of the larger Supertrees, offering staggering views of the Gardens and bits of the Singapore cityscape beyond.

Cloud Forest

A short walk from the Supertrees, you can find a pair of climate-controlled bio-domes. One is the Flower Dome, which keeps a dry climate of between 23-25° C (73-77° F) and features a range of plants from Mediterranean, Australian, South American and South African regions. I didn't have time to get in and have a look at that one – time and the hot, humid weather steered me toward the other instead – the Cloud Forest.

The Cloud Forest is a man-made mountain inside a climate-controlled dome that replicates the cool, moist conditions on top of tropical mountains between 1,000 and 3,000 m (3,300 to 9,800ft) above sea level.

At the entrance you're greeted by a refreshing blast of cool air, followed by the sight of the world's tallest indoor waterfall, which rains down water and mist from 35 m (115 ft) above the floor.

Taking an elevator to the top level brings you to a mossy, ferny "lost world" garden, after which you circle the mountain on the way down via a series of huge skyways that provide a series of spectacular views, both of the mountain itself, as well as the rest of the facility and out across the bay to the city.

Half way down, the Crystal Mountain cave features a variety of stalactites, stalagmites and hollowed-out crystals, and after that you're taken through the +5° C video presentation room, which demonstrates the effect that a 5° C (+9° F) increase in temperature due to climate change is expected to have on mountain-top environments like these.

Tickets to the Cloud Forest are SG$28 (US$22.40), including access to the Flower Dome as well. It goes without saying, this is a heck of an experience!