Mahouts return home with their elephants carrying grass to feed them on the eve of the rhino census in Kaziranga National Park in Assam state, India, 24 March 2015. Kaziranga will be closed to visitors for the next two days for a census of the rhinos commencing 25 March, in a previous census in 2013 in the park the population of the Indian rhinos was 2329. (Photo by EPA/Stringer)

A woman whose livelihood depends on selling recyclable wastes collects trash from a dumping site while surrounded by Marabou storks on the outskirts of Uganda's capital Kampala March 31, 2015. (Photo by James Akena/Reuters)

The Berenson robot strolls among visitors during the exhibition “Persona : Oddly Human” at the Quai Branly museum in Paris, France, February 23, 2016. The Berenson robot, developed in France in 2011, is the brainchild of anthropologist Denis Vidal and robotics engineer Philippe Gaussier. Its programming allows it to record reactions of museum visitors to certain pieces of art and then use the data to develop its own unique taste, which allows “Berenson” to judge whether or not it likes a certain work of art within an exhibition. (Photo by Philippe Wojazer/Reuters)

Emilia Pechinkova, a 24-years-old Bulgarian Pomak (Bulgarian speaking Muslims) bride poses for a photograph following the “gelina” or face painting ceremony carried out by female guests and relatives in preparation for her three-day wedding ceremony in the village of Draginovo, 100 kms southeast of Sofia on April 22, 2016. Bulgaria's Muslim population is one of the highest in the European Union. During the Communist regime religious rituals were not tolerated, and Muslims were forced to abandon wearing their traditional wedding outfits. Recently, more young Pomak women want to include traditional wedding customs that were forbidden during the regime, regardless of their secular lifestyles and the high cost of such a wedding. (Photo by Nikolay Doychinov/AFP Photo)

Nick Franklin, in action during the FMX competition at the 23rd edition of Free4Style this Saturday, July 2, 2016 in Estavayer-le-Lac,Switzerland. (Photo by Jean-Christophe Bott/Keystone/APA)

Kira Walkenhorst of Germany (L) signals as Doaa Elghobashy of Egypt (R) watches during the women's Beach Volleyball preliminary pool D game between Ludwig/Walkenhors of Germany and Elghobashy/Nada of Egypt the Rio 2016 Olympic Games at the Beach Volleyball Arena on Copacabana Beach in Rio de Janeiro, Brazil, 07 August 2016. (Photo by Antonio Lacerda/ANSA)

World Champion Matthias Dolderer of Germany flies over the Horseshoe Bend near Lake Powell in Page, United States during the transfer flight from Indianapolis to Las Vegas to prior the final stage of the Red Bull Air Race World Championship on October 12, 2016. (Photo by Predrag Vuckovic/AFP Photo)

“The September 11 attacks (called September 11, September 11th or 9/11), were a series of four coordinated suicide attacks against targets in New York City and the Washington, D.C. area on September 11, 2001. On that morning, 19 terrorists from the Islamist militant group al-Qaeda hijacked four passenger jets. The hijackers intentionally crashed two planes into the Twin Towers of the World Trade Center in New York City; both towers collapsed within two hours. Hijackers crashed a third plane into the Pentagon in Arlington, Virginia. When passengers attempted to take control of the fourth plane, United Airlines Flight 93, it crashed into a field near Shanksville, Pennsylvania, preventing it from reaching its intended target in Washington, D.C. Nearly 3,000 died in the attacks”. – Wikipedia

Photo: A firefighter breaks down after the World Trade Center buildings collapsed September 11, 2001 after two hijacked airplanes slammed into the twin towers in a terrorist attack. (Photo by Mario Tama/Getty Images)