A coil-shaped Helix Nebula showing a fine web of filamentary “bicycle-spoke” features embedded in the colorful red and blue ring of gas. At 650 light-years away, the Helix is one of the nearest planetary nebulae to Earth. A planetary nebula is the glowing gas around a dying, Sun-like star. (Photo by Reuters/NASA)

Fireworks explode above St. Basil's cathedral during a rehearsal for the “Spasskaya Tower” international military music festival at Moscow's Red Square, September 4, 2015. Military bands from different countries will participate in the annual tattoo starting on Sunday. (Photo by Maxim Zmeyev/Reuters)

Pedestrians walk past a truck with a giant Soviet Red Army hat seen on it, an installation created by Russian artist Vasily Slonov, during the annual “Winter Virage” motor sports festival dedicated to the Defender of the Fatherland Day on the embankment of the Yenisei River in Russia's Siberian city of Krasnoyarsk, February 23, 2015. (Photo by Ilya Naymushin/Reuters)

A woman holds a parasol as she stands in a field of fireweed, or Kochia scoparia, on a sunny autumn day at the Hitachi Seaside Park in Hitachi, north of Tokyo, October 26, 2015. Fireweed is a grass bush that takes on a bright red colour in autumn. (Photo by Thomas Peter/Reuters)

A Filipino transgender woman holds a huge red ribbon symbolizing fight against the HIV virus as she poses before photographers, during a World Aids Day celebration in Manila, Philippines, December 1, 2015. (Photo by Erik De Castro/Reuters)

Russian communists lay flowers at Soviet leader Joseph Stalin's tomb on Red Square next to the Kremlin wall in Moscow, Russia, December 21, 2015. Russian communists are marking the 136th anniversary of Josef Stalin's birthday. (Photo by Sergei Ilnitsky/EPA)

A young woman holds her smartphone at Red Square with the Kremlin's Spasskaya Tower, right, and St. Basil Cathedral, center, in the background in Moscow, Russia, Monday, July 25, 2016. (Photo by Pavel Golovkin/AP Photo)

Rescued Dutch hikers exit a search and rescue snowcat after they were brought safely to Grotli, Norway, February 26, 2016. Thirteen Dutchmen who were stranded while hiking in central Norway's mountains were found after snowmobile patrols by the Red Cross. Snowcats from the Red Cross are now moving ahead to pick the hikers up. (Photo by Torstein Boe/Reuters/NTB Scanpix)