Harris & Ewing Inc. photographed people, events, and architecture, particularly in Washington, D.C., during the period 1905-1945. Photo: Tests of Curtiss Palne for Army, Single Control. Created by Harris & Ewing. Published in 1912.

A military guard observes from a watch tower at the Combinado del Este prison during a media tour in Havana, Cuba, Tuesday, April 9, 2013. Cuban authorities led foreign journalists through the maximum security prison, the largest in the Caribbean country that houses 3,000 prisoners. Cuba says they have 200 prisons across the country, including five that are maximum security. (Photo by Franklin Reyes/AP Photo)

Google has built its first self-driving car prototypes and hopes to test hundreds more models this summer. If all goes well, the company is planning a pilot program in California over the next few years.

“Tardigrades (commonly known as waterbears or moss piglets) are small, water-dwelling, segmented animals with eight legs. Tardigrades were first discovered in 1773 by Johann August Ephraim Goeze, who called them kleiner Wasserbär, meaning “little water bear” in German. The name Tardigrada means “slow walker” and was given by Lazzaro Spallanzani in 1777. The name water bear comes from the way they walk, reminiscent of a bear's gait. The biggest adults may reach a body length of 1.5 millimetres (0.059 in), the smallest below 0.1 mm. Freshly hatched tardigrades may be smaller than 0.05 mm”. – Wikipedia. Photo: Tardigrades. (Photo by SPL/East News)

An adult specimen of Nannospalax (leucodon) montanosyrmiensis, a variant of the lesser mole-rat (Spalax leucodon) is pictured near Albertirsa, some 60 kilometers southeast of Budapest, Hungary, 12 May 2018. The critically endangered rodent lives in several isolated populations in the Carpathian Basin. (Photo by Sandor Ujvari/EPA/EFE)

When it opened in 1955, the Grande Hotel in the Indian Ocean city of Beira was one of the most luxurious in Africa. Photojournalist Fellipe Abreu documents the lives of the 3,500 people who now fill this long-closed hotel to capacity. (Photo by Fellipe Abreu/The Guardian)

An art installation formed with milk churns, made by land art artist Gerard Benoit a la Guillaume, is seen at the Chenau de Mayen in the resort of Leysin, Switzerland August 7, 2015. More than 80 milk churns were placed between the Tour d'Ai and the Tour de Mayen summits at an altitude of 2,000 meters (6,561 feet) above sea level under the direction of the artist, to be photographed for his ongoing art project entitled “Milk churns without borders”. (Photo by Denis Balibouse/Reuters)

A mahout rides on an elephant in the city of Amritsar, India, 08 November 2015. Such elephants are often accompanied by their caretakers who ask for alms from people in the streets. (Photo by Raminder Pal Singh/EPA)