A fellow officer comes to the aid of injured patrolman C.V. Satt, who was pelted with rocks and beer bottles during a clash between police and relief demonstrators in Denver September 23, 1935. (Photo by Henry G. Eisenhand/AP Photo)

“The telectroscope (also referred to as “electroscope”) was the first non-working prototype (i.e. conceptual model) of a television or videophone system. The term was used in the 19th century to describe science-based systems of distant seeing. The name and its concept came into being not long after the telephone was patented in 1876, and its original concept evolved from that of remote facsimile reproductions onto paper, into the live viewing of remote images”. – Wikipedia

Photo: Visitors to London wave to people they can see in New York as they peer through the Telectroscope situated by Tower Bridge on May 23, 2008 in London, England. The device named the Telectroscope provides a live visual link up between London and New York, to another Telectroscope by Brooklyn Bridge. (Photo by Cate Gillon/Getty Images)

"Temptation", part of an installation from the artist-duo David Burns and Austin Young, appears among the works of 30 artists in the multimedia exhibition "The Value of Food: Sustaining a Green Planet" at the Cathedral of St. John the Divine, Wednesday, October 7, 2015, in New York. The exhibition, installed in the cathedral's seven chapels and 14 bays, explores food accessibility, sustainability and other food-related issues and runs through April 3, 2016. (Photo by Bebeto Matthews/AP Photo)

North Korean leader Kim Jong Un (3rd R) and wife Ri Sol Ju (4th L) enjoy an art performance given by the Chongbong Band to mark the 70th anniversary of the founding of the Workers' Party of Korea (WPK) in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang on October 19, 2015. (Photo by Reuters/KCNA)

“A Snail's Life”. Photographer Vyacheslav Mischenko captures gorgeous macro photographs of snails near his hometown of Berdichev, Ukraine. After being taught to hunt for mushrooms as a child, Vyacheslav has grown up with a keen eye for spotting critters on the forest floor. Here, a snail takes shelter while perching on a leaf. (Photo by Vyacheslav Mischenko/Caters News)

A photographer has captured these eerie images showing the scale of some of Britain's deepest darkest wonders. Mike Deere, from Reading, heads to daunting locations such as abandoned mine shafts, miles of sewer tunnels that snake underneath London and even disused cooling towers. Photo: This incredible picture was taken at the Box Freestone Mine, in Wiltshire. Mike revealed that even experienced map readers would struggle to navigate their way around the seemingly endless tunnels that he and his friends visit. (Photo by Mike Deere/Caters News)

An animatronic polar bear visits the London Underground on January 23, 2015, to mark the launch of Fortitude, Sky Atlantic&Otilde's new drama starring Stanley Tucci, Michael Gambon and Christopher Ecclestone, which premieres on Thursday 29th January at 9pm. A team of 19 Hollywood prop specialists spent six weeks designing and building the realistic replica animal with six to eight people working on the costume at any one time, using over 60 different materials. (Photo by David Parry/PA Wire)

In this photo taken Saturday, January 24, 2015, a child makes a face while having her photo taken with the snow covered slopes of the Nanshan ski resort behind her in Beijing. As Beijing makes a final push in its bid for the 2022 Winter Olympics, Chinese President Xi Jinping says winning the bid will encourage over 300 million Chinese to take up winter sports by 2022, according to state-run Xinhua News agency. (Photo by Ng Han Guan/AP Photo)