Spectators in Moscow were treated to the site of humorously designed makeshift aircraft plunging into the Muskova River during the Red Bull Flugtag Moscow 2011 competition. 38 teams took part at the Flugtag – which means “flying day” – a competition in which teams in fancy dress attempt to pilot human-powered, home-made flying machines off a six-meter-high platform into water.

Photo: A makeshift aircraft plummets into the Moskva River during the Red Bull Flugtag Moscow 2011 competition. (Photo by Sergei Karpukhin/Reuters)

People gather at the site of a bomb explosion in Sanaa December 23, 2014. Five bombs exploded on Tuesday in Sanaa's old quarter, where many supporters of the Shi'ite Muslim Houthi group live, killing at least one person and wounding another, a Yemeni security official said. No one has claimed responsibility for the attacks, but the Houthis have been fighting the Sunni Islamist militant al Qaeda group and allied tribesmen since its gunmen captured Sanaa in September and forced the resignation of a government they had long seen as corrupt. (Photo by Khaled Abdullah/Reuters)

Local residents evacuate onto a street minutes after an earthquake in central Kathmandu, Nepal, May 12, 2015. A 7.3 magnitude earthquake killed at least 37 people and spread panic in Nepal on Tuesday, bringing down buildings already weakened by a devastating tremor less than three weeks ago and unleashing landslides in Himalayan valleys near Mount Everest. The earthquake was centered 76 km (47 miles) east of the capital in a hilly area close to the border with Tibet, according to coordinates provided by the U.S. Geological Survey. (Photo by Athit Perawongmetha/Reuters)

Tim Anderson final balanced rock stack in the Llano River. Tim Anderson, rock balancing “pro” from Pennsylvania, carefully worked to balance his stack on a dry spot in the Llano river Saturday March 12, 2016. He was an honored guest of the festival and enjoyed visiting Texas so he came for another year. The river was higher this year because of the rains so the balancers could not get to the better rock that were available last year. (Photo by Nell Carroll/American-Statesman)

Moscow riot police prepare to move on activists during an unsacnctioned anti-Putin opposition rally at the Pushkin Square March 5, 2012 in central Moscow, Russia. Amid charges of fraud, demonstrators took to the streets a day after Vladimir Putin declared victory in Russia's presidential elections. (Photos by: Rustem Adagamov; Source: LiveJournal; Gleb Shchelkunov; Source: LiveJournal; Ilya Varlamov; Source: LiveJournal; Raskalov; Source: LiveJournal; Dmitry Chistoprudov; Source: LiveJournal)

Paramedics carry an injured woman out from a subway station after a rush-hour subway train derailment, to be transported by a medical helicopter in Moscow, Russia, on Tuesday, July 15, 2014. A rush-hour subway train derailed in Moscow Tuesday, killing 20 people and injuring at least 150, emergency officials said. Several cars left the track in the tunnel after a power surge triggered an alarm, which caused the train to stop abruptly. (Photo by Ivan Sekretarev/AP Photo)

Students dance in the hallway during a break at Moscow State Academy of Choreography in Moscow, Russia 03 March 2016. Moscow State Academy of Choreography is the oldest institution in Moscow which teaches Ballet arts not only Russian citizens, but also representatives from more than 20 countries. (Photo by Yuri Kochetkov/EPA)