An American flag is visible in the windows of the cupola aboard the International Space Station. Thanks to a bill passed by Texas legislators in 1997 that put in place technical voting procedure for astronauts – nearly all of whom live in Texas – they have the ability to vote from space through specially designed absentee ballots. To preserve the integrity of the secret vote, the ballot is encrypted and only accessible by the astronaut and the county clerk responsible for casting the ballot. (Photo by NASA)

Marieke van der Meer from the Netherlands works on her sculpture “Flora” at the sand sculpture show in Binz on Ruegen island, Germany, 09 March 2016. With the motto “Fascination Nature”, 50 sand artists have created oversized sculptures. The sculptors use 16,000 tons of special sand that is pressed into big blocks first and then formed. The 7th sand sculpture show on 5,600 square meters of exhibition ground opens on 12 March 2016. (Photo by Ens Buettner/EPA)

On September 1, 2004, Chechen militants stormed an elementary school in the town of Beslan in the Russian republic of North Ossetia. They took 1,100 teachers, children, and their relatives hostage, demanding the withdrawal of federal forces from Chechnya as a condition for their release. On September 3, 2004, Russian security forces stormed the building, resulting in a battle in which more than 330 hostages died, including 186 children. Here: A man assists two young hostages who managed to escape from the school building after special forces entered the school in Beslan, North Ossetia, Friday 03 September 2004. (Photo by Yuri Kochetkov/EPA)

Iraqi pro-government forces fire an anti-tank cannon near al-Sejar village, north-east of Fallujah, on May 25, 2016, as they take part in a major assault to retake the city from the Islamic State (IS) group. Iraqi forces, consisting of special forces, soldiers, police, paramilitary-fighters and pro-government tribesmen, launched a major assault to retake Fallujah, the scene of deadly battles during the US occupation and one of the toughest targets yet in Baghdad's war on the Islamic State group. (Photo by Ahmad Al-Rubaye/AFP Photo)

Philippine Marines from the Naval Special Operations Group (NAVSOG) storm the beach to simulate an “extraction” of a kidnapped victim as they kick off a five-day amphibious military exercise at the Philippine Marines training center in Ternate, Cavite province, about 50 miles (80kms) south of Manila, Philippines Thursday, September 24, 2015. The naval exercise dubbed PAGSISIKAP 2015 is aimed at enhancing capability of their fleet and forces as well as to strengthen interoperability of the Marines. (Photo by Bullit Marquez/AP Photo)

An employee holds a plant with roots at the Plant Advanced Technologies (PAT) company greenhouse in Laronxe near Nancy, Eastern France, June 19, 2015. The farmers employed at the site in Laronxe are growing plants in a special way with a view to “milking” them for use in medicines, cosmetics and agrochemicals. Several major brands, including Germany's BASF and France's Chanel, have teamed up with Plant Advanced Technologies (PAT) in the hope of securing privileged access to the so-called “biomolecules” it extracts through the use of a patented technique. (Photo by Vincent Kessler/Reuters)

Todd Bretl specializes in underwater photography, and is able to capture striking photos of aquatic life big and small. His photos of sharks are particularly striking; though he rarely faces hostility from the animals, he tries not to spend too much time looking through his viewfinder and many shots are framed by educated guesses and impeccable timing. What follows are photographs taken over the past several years on trips to the Bahamas and Isla Guadalupe, an island off the coast of the Baja California peninsula in Mexico. (Photo by Todd Bretl)

A policewoman wipes her tears as she stands in front of metal caskets containing the bodies of Special Action Force (SAF) police who were killed in Sunday's clash with Muslim rebels, at Villamor Air Base in Pasay city, metro Manila January 29, 2015. Philippine President Benigno Aquino urged legislators on Wednesday not to abandon a plan for autonomy for Muslims to end a decades-old insurgency after the clash in which dozens of people were killed, saying doing so would dash hopes for peace. (Photo by Romeo Ranoco/Reuters)