Men rest after salvaging metal on the 30th floor of the “Tower of David” skyscraper in Caracas February 3, 2014. A 45-storey skyscraper in the center of Venezuela's capital Caracas is a slum, probably the highest in the world. Dubbed the “Tower of David”, the building was intended to be a shining new financial center but was abandoned around 1994 after the death of its developer – banker and horse-breeder David Brillembourg – and the collapse of the financial sector. (Photo by Jorge Silva/Reuters)

Capgrossos de Mataro team members fall during the 25th Castells' contest at the Tarraco Arena in Tarragona, Catalonia, northeastern Spain, 02 October 2016. The “Castells” is a popular event in which people create human towers up to a height of between six and ten levels. (Photo by Jaume Sellart/EPA)

Broadway Tower is a folly located on Broadway Hill, near the village of Broadway, in the English county of Worcestershire, at the second highest point of the Cotswolds after Cleeve Hill. Broadway Tower's base is 1,024 feet (312 metres) above sea level. The tower itself stands 55 feet (17 metres) high. The “Saxon” tower was designed by James Wyatt in 1794 in the form of a castle, and built for Lady Coventry in 1799. The tower was built on a “beacon” hill, where beacons were lit on special occasions. Lady Coventry wondered if a beacon on this hill could be seen from her house in Worcester – approximately 22 miles (35 km) away – and sponsored the construction of the folly to find out. The beacon could be seen clearly.

Members of the Castellers “Vila de Gracia” start forming their famous human tower called “castell” in the Barcelona neighborhood of Gracia, Catalonia, Spain on Sunday May 19 2013. A “castell” is a human tower traditionally built during festivals in many places in Catalonia. At these festivals, several "colles" or teams compete to build the most impressive towers they can. (Photo by Emilio Morenatti/Associated Press)

Jun Sato (2nd L), founder of Japan's first parkour educational institute SENDAI X-TRAIN, demonstrates his parkour skill with other practitionners at a park in Tokyo, Japan November 2, 2016. (Photo by Kim Kyung-Hoon/Reuters)

India: A sweeper cleans the side of a road near a replica of the Eiffel Tower amid heavy fog in the early morning in the northern Indian city of Chandigarh January 18, 2010. (Photo by Ajay Verma/Reuters)

A new LED light fixture is secured to the side of a lift as crews replace existing street lights August 1, 2011 in Las Vegas, Nevada. The new energy-efficient fixtures are expected to reduce the city's annual electricity use by eight million kilowatt hours, saving about USD 400,000. The city estimates the LEDs will last about 15 years, nine years longer than the current lights. Funding for the project comes from federal energy conservation bonds and an American Recovery & Reinvestment Act grant. The city plans to replace all of its 50,000 streetlights after more funding is secured. (Photo by Ethan Miller/Getty Images)

Construction work on the tower began in November 2008. Upon its completion this year the building will stand approximately 632 meters (2,073 ft.) high and will have 121 stories. It is expected to open to the public in 2015. (Photo by Rex Features)