The city's high-rises aren't the only things reaching sky-high in Hong Kong at the moment. The prices of the apartments housed in these buildings are also sky-rocketing. Apartment prices in Hong Kong have risen by 120 percent since 2009. The strongest increases are being seen in the luxury apartment segment. But even the city's so-called "Cages," small, literally two-square meter large boxes designed for sleeping, only start at the equivalent of around €100. Hong Kong is considered to be the city with the world's highest cost of living.