Roque de los Muchachos Helicopter Pads

The Roque de los Muchachos houses one of the world's largest collections of professional telescopes. The telescopes were put there after rigorous site testings and negotiations between governments of Spain and the Canary Islands. They formed the world's first international telescope collection, something that needed to be celebrated. 

The observatory as a whole was inaugurated on June 29, 1985, by a representative of each member country, including King Juan Carlos of Spain, Queen Beatrix of the Netherlands, Queen Margrethe II of Denmark, King Gustav of Sweden, the presidents of West Germany and Ireland, and the Duke of Gloucester, who represented Queen Elizabeth of the United Kingdom. The group was led from telescope to telescope to officially open each of them. 

With such high and dignified company, certain precautions had to be taken to not offend anyone. The most interesting of these precautions was the creation of four identical helicopter platforms. The four landing pads were meant to receive each of the four royal guests at the same time so there would be no controversy caused by having some dignified guests arrive before the others. 

After the big event, the landing pads largely fell out of use, though they are still in working order. Today, people visit the observatory via car, and are typically only flown out if they are ill.