French engineer and professional violinist Laurent Bernadac poses with the “3Dvarius”, a 3D printed violin made of transparent resin, during an interview with Reuters in Paris, France, September 11, 2015. (Photo by Christian Hartmann/Reuters)

241543903 (a.k.a “Heads in Freezers”) is a numerical keyword associated with a photo meme that involves people taking pictures with their heads in the freezer & sharing them online. By tagging a series of image files with a cryptic number, a high level of search engine optimization can be easily achieved. As a result, typing “241543903” into image search engines like Google Images successfully yields pages after pages of pictures showing people’s heads in freezers.

Axel, a research prototype rover for exploring the Moon, Mars and other planets, is remotely driven over rocks as engineers from Jet Propulsion (JPL) and grad students from Caltech (California Institute of Technology) demonstrate its mobile over the steep and rocky grounds of the JPL Mars Yard on January 14, 2009 in Pasadena, California. The rover is capable of descending cliffs or into craters and returning by a cable tethered to its starting point. Development of the Axel rover is a point effort funded by NASA Exploration Systems Mission Directorate (ESMD) and lead by Principal Investigator Issa Newnas and Co-Investigator and Caltech professor of mechanical engineering bio engineering Joel Burdick. (Photo by David McNew/Getty Images)

Bosnian worker Sefik Salihovic drives a steam engine in the Bosnian town of Banovici, 140 kms (86.9 miles) north of Sarajevo, on Monday, November 24, 2014. Every day, steam engines over 60 years old, defy their age and still pull wagons of coal from Banovici's coal mine to clients in nearby towns. But in the summer some of them turn into the only tourist attraction this impoverished north Bosnian town has to offer. (Photo by Amel Emric/AP Photo)

These eye-catching photographs capture the special relationship between a group of farmers and elephants – with a gorgeous sunset in the background. Vithun Khamsong, a civil engineer, shot the images earlier this year while visiting Surin, Thailand. (Photo by Vithun Khamsong/Caters News Agency)

Expedition 44 flight engineer and NASA astronaut Scott Kelly seen inside the Cupola, a special module which provides a 360-degree viewing of the Earth and the International Space Station. Kelly is one of two crew members spending an entire year in space. (Photo by Scott Kelly/NASA)

Competitors ride a home-made vehicle without an engine on a downhill track in the Red Bull Soapbox Race in Santiago, Chile, November 27, 2016. (Photo by Jonathan Faus/Reuters)

People watch a competitor riding a homemade vehicle without an engine on a 300-metre-track during the Red Bull Soapbox Race in Amman, Jordan September 4, 2015. (Photo by Muhammad Hamed/Reuters)