The pool at the top of Hong Kong's International Commerce Centre should probably serve up altitude-sickness medicine with its pool towels. That's because the pool, part of the Ritz-Carlton Hotel, is roughly 1,600-ft. (490 m) off the ground. Opened in March 2011, the infinity-style amenity comes complete with LED screens that cover the ceiling and one wall so visitors can enjoy a view of coral reefs and peaceful skies, as well as the (real) Victoria Harbor below, while they swim.