ESA astronaut Samantha Cristoforetti on the International Space Station 3 February 2015 during her Futura mission. Samantha is living and working on the Station as part of the Expedition 42 crew. Picture released on February 10, 2015. (Photo by ESA/NASA)

Vietnamese military personnel in traditional dress take part in a parade celebrating the 40th anniversary of the end of the Vietnam War which is also remembered as the fall of Saigon, in Ho Chi Minh City, Vietnam, Thursday, April 30, 2015. (Photo by Dita Alangkara/AP Photo)

Couples take part in a Valentine's Day attempt to break the record for the world's largest simultaneous gay kiss on February 14, 2004 in Rome, Italy. (Photo by Franco Origlia/Getty Images)

Fascist youth, both boys and girls, in the rebel uniforms in Irun after the city had been captured by the rebels. (Photo by Maeers/Fox Photos/Getty Images). 13th November 1936

In this handout photograph received from the Delhi Police at the scene of the incident, an Indian schoolboy is confronted by a white tiger inside its enclosure at the Delhi Zoo in New Delhi on September 23, 2014. A white tiger on September 23 attacked and killed a schoolboy who appeared to have jumped or fallen into its enclosure at the zoo in the Indian capital, witnesses said. (Photo by AFP Photo/Delhi Police)

A dinosaur robot produced by Tyco Electronics Japan G.K. is controlled by a smartphone at CEATEC (Combined Exhibition of Advanced Technologies) Japan 2014 held at at Makuhari Messe in Chiba, east of Tokyo, Japan, 07 October 2014.With a Sharp Aquos ZETA mobile phone model, users can make the 6.5-meter (21 feet, 4 inches) long, 2.1-meter (6 feet, 11 inches) tall dinosaur robot to walk forward and backward, jump, move its head, hands and legs up and down, left and right, open and close its mouth by touching the screen panel and make it bark by shaking the handheld. (Photo by Kimimasa Mayama/EPA)

A basket of olives sits in an olive tree field in La Rinconada, near the Andalusian capital of Seville September 24, 2012. (Photo by Marcelo del Pozo/Reuters)

Military vehicles surround a wreckage of a trolleybus, in Volgograd, Russia, Monday, December 30, 2013. A bomb blast tore through a trolleybus in the city of Volgograd on Monday morning, killing at least 10 people a day after a suicide bombing that killed at least 17 at the city's main railway station. Volgograd is about 650 kilometers (400 miles) northeast of Sochi, where the Olympics are to be held. (Photo by Denis Tyrin/AP Photo)