A four-year-old dog Nika stands next to an image of Cuba's revolutionary hero Ernesto “Che” Guevara in front of a flooded street in Havana, January 23, 2016. Havana's seafront Malecon continued to be slammed by massive waves that flooded parts of the seaside city on Saturday. As a result, Havana was confronting flooding as a cold front passes through the Caribbean island. The giant waves began washing up onto shore during sunrise. The waves have been accompanied by winds passing through at a speed between 35 and 50 km (21 to 31 miles) per hour. (Photo by Alexandre Meneghini/Reuters)

A “Maya” girl sits in an altar during the traditional celebration of “Las Mayas” on the streets in Madrid, Spain Sunday, May 10, 2015. The festivity of the Maya comes from pagan rites and dates from the medieval age, appearing in ancient documents. It takes place every year in the beginning of May and celebrates the beginning of the spring. Girls between 7 and 11 years old are chosen as “Maya” and should sit still, serious and quiet for a couple of hours in altars on the street decorated with flowers and plants and afterwards they walk to the church with their family where they attend a ceremony. (Photo by Daniel Ochoa de Olza/AP Photo)

Rope access technicians carry out maintenance service on wind turbines including repairs, blade inspections and cleaning in Izmir, Turkey on February 19, 2021. In Turkey, where investments in renewable energy has increased, there are wind tribunes over 3,500. (Photo by Mahmut Serdar Alakus/Anadolu Agency via Getty Images)

Greek actress Katerina Lehou, playing the role of High Priestess, lights a torch during the dress rehearsal for the Olympic flame lighting ceremony for the Rio 2016 Olympic Games at the site of ancient Olympia in Greece, April 20, 2016. Fire spurted from the concave mirror as a priestess, kneeling in her long, pleated dress before a ruined Greek temple, focused the blazing sun's rays on her metal torch. Come rain or shine on Thursday's official lighting ceremony, Rio de Janeiro has now secured its Olympic flame, which will burn in the main Olympic stadium throughout the Aug. 5-21 games. (Photo by Yannis Behrakis/Reuters)

“NASA's Pathfinder, Pathfinder Plus, Centurion and Helios Prototype were an evolutionary series of solar- and fuel-cell-system-powered unmanned aerial vehicles. AeroVironment, Inc. developed the vehicles under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program. They were built to develop the technologies that would allow long-term, high-altitude aircraft to serve as “atmospheric satellites”, to perform atmospheric research tasks as well as serve as communications platforms”. – Wikipedia

Photo: The solar-electric Helios Prototype flying wing is flies over the Hawaiian islands of Niihau and Lehua during the first solar-powered test flight July 14, 2001 from the U.S. Navy's Pacific Missile Range Facility on Kauai, HI. The 18-hour flight was a functional checkout of the aircraft's systems and performance in preparation for an attempt to reach sustained flight at 100,000 feet altitude later in the summer. (Photo Courtesy of NASA/Getty Images)

A “Maya” girl sits in an altar during the traditional celebration of “Las Mayas” on the streets in Colmenar Viejo, near Madrid, Spain, Friday, May 2, 2014. The festivity of the Maya comes from pagan rites and dates from the medieval age, appearing in ancient documents, it takes place every year in the beginning of May and celebrates the beginning off the spring. A girl between 7 and 11years is chosen as “Maya” and should sit still, serious, and quiet for a couple of hours in an altar on the street decorated with flowers and plants, afterwards they walk to the church with their family where they attend a ceremony. (Photo by Daniel Ochoa de Olza/AP Photo)

“Theyyam”. Preparation for the Theyyam performance in the surroundings of Kasaragod city. Theyyam is a popular ritual dance form of North Kerala, particularly in Kannur and Kasargod districts. The Theyyam represents a mythological, divine or heroic character. Make up of Theyyams is done by specialist. There are different types of face painting for which primarily and secondary colours are used. Therefore it is essential that the makeup man should have perfect knowledge of primary and secondary colour combinations. Sometimes, it takes several hours to paint each face. Photo location: Kasaragod, India. (Photo and caption by Rafal Ziejewski/National Geographic Photo Contest)

Students receive a group punishment during a military-style close-order drill class at the Qide Education Center in Beijing February 19, 2014. The Qide Education Center is a military-style boot camp which offers treatment for internet addiction. As growing numbers of young people in China immerse themselves in the cyber world, spending hours playing games online, worried parents are increasingly turning to boot camps to crush addiction. Military-style boot camps, designed to wean young people off their addiction to the internet, number as many as 250 in China alone. (Photo by Kim Kyung-Hoon/Reuters)