“Hippo Chase”. As we approached the camp the Selinda Reserve of northern Botswana our boat passed by a hippo resting in the water. I turned around to look back at the boat's wake and saw the hippo charging after us! The hippo must've been tired from an all-nighter because he was angry. He rose way up out of the water three times trying to chase our boat! He was coming at us with such force that he created a wake of his own. Photo location: Selinda Reserve of northern Botswana. (Photo and caption by Curtis Simmons/National Geographic Photo Contest)

“Igor Sikorsky (May 25, 1889 – October 26, 1972), born Igor Ivanovich Sikorsky was a Russian American pioneer of aviation in both helicopters and fixed-wing aircraft. He designed and flew the world's first multi-engine fixed-wing aircraft, the Russky Vityaz in 1913, and the first airliner, Ilya Muromets, in 1914. After immigrating to the United States in 1919, Sikorsky founded the Sikorsky Aircraft Corporation in 1923, and developed the first of Pan American Airways' ocean-conquering flying boats in the 1930s. In 1939 Sikorsky designed and flew the Vought-Sikorsky VS-300, the first viable American helicopter, which pioneered the rotor configuration used by most helicopters today. Sikorsky would modify the design into the Sikorsky R-4, which became the world's first mass-produced helicopter in 1942”. – Wikipedia

Photo: Westland Sikorsky H-5's, used by British European Airways Helicopters, which fly between London and Birmingham. The Sikorsky H-5, (aka R-5, S-51, HO3S-1, or Horse) (R-5 until 1948; company designation VS-327) is a helicopter built by Sikorsky Aircraft Corporation, formerly used by the United States Air Force, and its predecessor, the United States Army Air Forces, as well as the United States Navy and United States Coast Guard (with the designations HO2S and HO3S). (Photo by Harrison /Topical Press Agency/Getty Images). 22nd May 1951

A marine aims an RPG-7, a portable rocket- propelled grenade launcher, during military exercises conducted by the Russian Pacific Fleet' s naval infantry unit at the Bamburovo firing range on February 2, 2017. The drills are a part of preparations for the Suvorov Attack and Sniper Line army competitions. (Photo by Yuri Smityuk/TASS)

People look out at the city among 30,375 square feet of mirrors at SUMMIT One Vanderbilt in New York on May 22, 2024. The Parade of Ships is seen from SUMMIT One Vanderbilt in NYC as part of the Fleet Week Celebration events. (Photo by Timothy A. Clary/AFP Photo)

A Sukhoi Su-35S jet fighter of the Russian Knights aerobatic team performs during the International Maritime Defence Show “Fleet-2024” in Kronstadt, outside St. Petersburg, Russia, Friday, June 21, 2024. (Photo by Dmitri Lovetsky/AP Photo)

A French soldier stands near a military combat command vehicle on display at The Defence and Security Exhibition on September 13, 2011 in London, England. ExCeL London is hosting the exhibition with hundreds of manufacturers from all over the world displaying their hardware. (Photo by Peter Macdiarmid/Getty Images)

A worker carries a tray of boiled tofu in a traditional tofu factory in Depok, Indonesia, 21 January 2015. Tofu has been a common side dish for many Indonesian families. It is healthy, inexpensive and easy to find throughout the city. Tofu entrepreneurs in Indonesia are suffering due to the weakening of the rupiah against the US dollar and the rise in prices of imported soybeans in the international market, forcing tofu-makers to cut their production and lay off staff. (Photo by Adi Weda/EPA)

This artwork created using the end of a drill is the work of Swiss photographer Fabian Oefner who captures the flight of paint in just one 40,000th of a second. His latest Black Hole series celebrates the physics of centripetal force and the effects it has on simple paint and a an ordinary drill with a metal rod connected on the end. The incredible result of Fabians work comes out looking like a picture taken on the Hubble Telescope of some cosmic event. (Photo by Fabian Oefner/Caters News)