Tao Xiangli gets out of his homemade submarine after operating it in a lake on the outskirts of Beijing September 3, 2009. Amateur inventor Tao, 34, made a fully functional submarine, which has a periscope, depth control tanks, electric motors, manometer, and two propellers, from old oil barrels and tools which he bought at a second-hand market. He took 2 years to invent and test the submarine which costs 30,000 yuan ($4,385). (Photo by Christina Hu/Reuters)

Afghan protesters beat a policeman after a suicide attack that targeted crowds of minority Shiite Hazaras during a demonstration at the Deh Mazang Circle of Kabul on July 23, 2016. Islamic State jihadists claimed responsibility for twin explosions July 23 that ripped through crowds of Shiite Hazaras in Kabul, killing at least 61 people and wounding 207 others in apparently their deadliest attack in the Afghan capital. The bombings during a huge protest over a power transmission line could deepen sectarian divisions in a country well known for communal harmony despite decades of war. (Photo by Wakil Kohsar/AFP Photo)

Members of the Women's Fire Brigade with their Chief Officer, March 1916. (Photo by Topical Press Agency)

Microsoft co-founder Paul Allen has spent the last six years working on a giant aircraft capable of launching rockets to space. Today, his company Stratolaunch Systems literally rolled that plane out of its hangar in the Mojave Desert for the first time ever.

A mechanic examines a Gogoro Smartscooter which is connected to a tablet, in its shop in Taipei, Taiwan, July 6, 2015. Companies such as electric motor scooter firm Gogoro could hold the key to Taiwan's economic growth. In just three years, the start-up raised $150 million to develop the smartphone-synched bike, and a charging network for it. Gogoro's success in creating a home-grown, innovative product is precisely what Taiwan's government wants to foster as it seeks to reduce the export-driven economy's reliance on the island's world-class tech manufacturing sector. (Photo by Pichi Chuang/Reuters)

Nicholas Mee & Co, an Aston Martin Heritage Dealer in West London, have just finished putting the final touches to a fully functional kid-sized car inspired by the legendary Aston Martin DB models of the 1960s. But this is no rickety pedal car. It has a steel chassis, composite bodywork, leather seats, a wood rimmed steering wheel and Brembo disc brakes.

An Army Sikorsky R-5 helicopter, undergoing record trials, demonstrates its lifting power by carrying 17 persons and pilot aloft as female onlookers wave in Bridgeport, Conn., January 10, 1946. During the tests records were claimed for altitude speed and both altitude and speed with payload. (Photo by Anthony Camerano/AP Photo)

Russian President Vladimir Putin, right, and North Korea's leader Kim Jong Un pose for photographers during their meeting in Vladivostok, Russia, Thursday, April 25, 2019. Putin and Kim are set to have one-on-one meeting at the Far Eastern State University on the Russky Island across a bridge from Vladivostok. The meeting will be followed by broader talks involving officials from both sides. (Photo by Alexander Zemlianichenko/AP Photo/Pool)