Torres KIO (Puerta de Europa), Madrid

Built of granite, glass and metal, the angle at which these towers lean is simply spectacular. They're 27 stories high and a shining example of how dynamic and modern Madrid has become. Their official name is Puerta de Europa (Gateway to Europe), though locals call them the KIO Towers after the business group in charge of their construction. They were eventually completed in 1996 by the banking group Caja Madrid. Architects Philip Johnson and John Burgee (famous for New York's AT&T tower) designed them as office space and they're the most dramatic sight on the skyline as you arrive from the north. They are not open to the public.