A small section of the expanding remains of the Veil Nebula, a massive star that exploded about 8,000 years ago. The entire nebula is 110 light-years across, covering six full moons on the sky as seen from Earth, and resides about 2,100 light-years away in the constellation Cygnus, the Swan. (Photo by Reuters/NASA/ESA/Hubble)

A man carries an injured girl after what activists said were five air strikes by forces loyal to Syria's President Bashar al-Assad in Douma, eastern al-Ghouta, near Damascus September 11, 2014. (Photo by Bassam Khabieh/Reuters)

A 19th century bicycle safety lock is displayed in an old frame in the Museum of Domenico Agostinelli in Dragona, near Rome October 30, 2014Italian collector Domenico Agostinelli, 74, has a passion that has led him over the past 60 years to pick up and collect things of all types, from antique art to everyday objects of the past and present. His collection includes a 65-million-year-old dinosaur egg, meteor fragments, a car that once belonged to American mob boss Al Capone, a lock of hair of Italian national hero Giuseppe Garibaldi, toys, weapons, musical instruments of all kinds and many more. (Photo by Tony Gentile/Reuters)

An African giant pouched rat sniffs for traces of landmine explosives at APOPO's training facility in Morogoro on June 17, 2016. APOPO trains the rats to detect both tuberculosis and landmines at its facility. Every year landmines kill or maim thousands of people worldwide. The trained rats sniff for explosive and so are able to detect the presence of landmines far faster than conventional methods which involve metal detection. (Photo by Carl De Souza/AFP Photo)

Cambodian children sleep on a pavement at a park in Phnom Penh on July 8, 2016. (Photo by Tang Chhin Sothy/AFP Photo)

Two female soldiers have their picture taken by an army colleague at Mangyongdae. (Photo by Gavin John/Mediadrumworld.com)

A monkey leaps into a pond on a hot day in Allahabad on May 19, 2017. According to local reports temperatures have soared in the northern Indian city to 47.28 Celsius. (Photo by Sanjay Kanojia/AFP Photo)

Former Olympic gymnast Nastia Liukin performs a flip while throwing the ceremonial first pitch during a baseball game between the Los Angeles Angels and the Tampa Bay Rays, Friday, July 14, 2017, in Anaheim, Calif. (Photo by Jae C. Hong/AP Photo)