Senator Barack Obama (D-IL) (R) stands in front of Senator Hillary Clinton (D-NY) as they arrive for U.S. President George W. Bush's annual State of the Union speech to a joint session of Congress at the U.S. Capitol in Washington in this January 23, 2007 file photo. Hillary Clinton announced her second run for the presidency on April 12, 2015 starting her campaign as the Democrats' best hope of fending off a crowded field of lesser-known Republican rivals and retaining the White House. (Photo by Larry Downing/Reuters)

The competition, which is run by the Royal Observatory Greenwich in association with BBC Sky at Night Magazine, is now in its sixth year and has received over 2,500 entries. Photo: Centre of the Heart Nebula by Ivan Eder (Hungary). Situated 7500 light years away in the “W”-shaped constellation of Cassiopeia, the Heart Nebula is a vast region of glowing gas, energized by a cluster of young stars at its centre. The image depicts the central region, where dust clouds are being eroded and moulded into rugged shapes by the searing cosmic radiation. (Photo by Ivan Eder)

Artist Heather Dewey-Hagborg's 'Stranger Visions', comprising of 3D printed faces extracted from DNA taken from discarded cigarette butts and chewing gum, is displayed at the Big Bang Data exhibition at Somerset House on December 2, 2015 in London, England. The show highlights the data explosion that's radically transforming our lives. It opens on December 3, 2015 and runs until February 28, 2016 at Somerset House. (Photo by Peter Macdiarmid/Getty Images for Somerset House)

The work entitled “Trip 1, Trip II, Trip III” by April Pine is pictured before dawn at Sculpture By The Sea at Bondi Beach on October 19, 2017 in Sydney, Australia. This year the outdoor exhibition celebrates its 21st birthday with 104 exhibiting artists from Australia and around the world and runs from the 19th October-5th November 2017. (Photo by Brook Mitchell/Getty Images)

A supporter of the presidential candidate for the Honduran Opposition Alliance Against the Dictatorship for the past election, Salvador Nasralla, lies on the street in front of police officers during a demonstration against the contested re-election of President Juan Orlando Hernandez, in Tegucigalpa, Honduras on January 21, 2018. (Photo by Orlando Sierra/AFP Photo)

A British Museum representative poses for photographs next to Andy Warhol's “Mao”, left, and Jim Dine's “Drag: Johnson and Mao” which feature in “The American Dream: pop to the present” exhibition during a media photocall at the British Museum in London, Monday, March 6, 2017. The exhibition, which opens to the public from March 9 and runs until June 18, charts modern and contemporary print making. (Photo by Matt Dunham/AP Photo)

The Moonlight Rainbow Fountain is the world's longest bridge fountain that set a Guinness World Record with nearly 10,000 LED nozzles that run along both sides that is 1,140m long, shooting out 190 tons of water per minute. Installed in September 2009 on the Banpo Bridge, former mayor of Seoul Oh Se-hoon declared that the bridge will further beautify the city and showcase Seoul's eco-friendliness, as the water is pumped directly from the river itself and continuously recycled. The bridge has 38 water pumps and 380 nozzles on either side, which draw 190 tons of water per minute from the river 20 meters below the deck, and shoots as far as 43 meters horizontally.

“Einar Erici (1885–1965) was a physician by profession, working at a tuberculosis hospital in Stockholm, even running a private medical practice. He was by then the most renowned Swedish expert of church organs and organ builders, and his archival collection is today held by the Swedish National Heritage Board. This archive includes mostly writings, such as letters and manuscripts for published articles and essays, but also more than 2 000 black and white photos – original prints, glass plates and film negatives”. – Swedish National Heritage Board

Photo: Priest, Valamo Monastery, Karelia, Russia (then Finland), 1930s. Father Venerius with a birchbark basket. (Photo by Einar Erici)