The two Kio Towers are one of the most famous elements of the Madrid skyline. These two buildings have been officially named “The Door to Europe,” as they can easily be noticed for their location: the heart of Plaza de Castilla, their height: 377 feet high; and their architecture: They are two leaning towers, symmetrical with the La Castellana axis, forming a type of futuristic door defying the laws of gravity.

Also known as the Kio Towers (the name of the main shareholding company of the development group), the construction of the buildings started in 1990, using the design of the John Burgee Architects New York Studio, and was finished in the fall of 1995. The sides of the square bases of the towers are 115 feet. The towers lean at an angle of 14.3 degrees each.

Each skyscraper has three basements, a ground floor, an equipment floor, and 24 office floors, with a size of about 12,900 square feet. Moreover, it has a top floor with a heliport on each tower. Eight elevators provide access to the upper floors. However, due to the leaning shape of the building, four of them only reach the 13th floor. This leaning makes every floor different from the others, as space limitations differ with respect to the central elevator area. The façades are a mixture of glass, aluminium, and stainless steel, whose combination makes up the enormous bright bands typical of this pair of skyscrapers.