One of the most dangerous structures in the world

Located in Madrid, Spain, the Puerta de Europa (or Gate of Europe) is a structure composed of two identical, tilted towers. The structure was built between 1989 and 1996 as a joint project between American and Spanish architectural firms. Each building has 26 floors, a vertical of 114 meters (374 feet), with a 15 degree incline towards the other. The west tower has a rooftop helicopter pad outlined in blue, whereas the east tower has a red one.