Swim MARINA BAY SANDS casino POOL, Singapore

Go swimming in the sky at the Marina Bay Sands Singapore. This giant hotel/casino complex is capped by an unparallelled infinity pool in which swimmers can do laps high in the sky. More than 650 feet above ground, swimmers splash around in a swimming pool that's over 490 feet long, and appears to drop off into the abyss.

The Sands SkyPark in Singapore is an awe-inspiring engineering wonder. This unique structural masterpiece, designed by visionary architect Moshe Safdie, floats atop the three soaring Marina Bay Sands hotel towers 200m in the sky. At the top of the 55 storey building is a 150-meter infinity swimming pool.
But swimming to the edge won't be quite as risky as it looks. While the water in the infinity pool seems to end in a sheer drop, it actually spills into a catchment area where it is pumped back into the main pool. The pools have two circulation systems. The first functions like that of a regular pool, filtering and heating the water in the main pool. The second filters the water in the catch basin and returns it to the upper pool.
The infinity pool on the roof of SkyPark spans the three towers of the hotel. The platform itself is longer than the Eiffel tower laid down and is one of the largest of its kind in the world. At three times the length of an Olympic pool and 650ft up, it is the largest outdoor pool in the world at that height.
Source: amusingplanet.com