Mario Huettenhofer, chief of the German company 3D Fab, presents his own face as 3d print during the international fairs FabCon 3.D and Rapid.Tech in Erfurt, Germany, Thursday, May 15, 2014. 130 exhibitors from all over the world present the entire world of 3D printing. The trade fairs are accompanied by specialist programs featuring 80 scientists, practitioners and trend analysts from ten countries, who will explain the latest findings, trends and applications for additive processes in industry and for 3D printing in the private sector to newcomers, experts and consumers alike. (Photo by Jens Meyer/AP Photo)

Italian Air Force's aerobatic demonstration team, the Frecce Tricolori leave colourful vapour trails as they fly over the Altare della Patria monument on Republic Day (Festa della Repubblica) in Rome, Italy, 02 Jun 2017. The anniversary marks the founding of the Italian Republic in 1946. (Photo by Massimo Percossi/EPA)

Ukrainians jump over a bonfire in Kiev, Ukraine, 06 July 2019, as they celebrate the traditional pagan holiday of Ivana Kupala. Ivana Kupala is celebrated, during the summer solstice, on the shortest night of the year, marking the beginning of summer and is celebrated in Ukraine, Belarus, Poland and Russia. People sing and dance around bonfires, play games and perform traditional rituals. Young people jump over bonfires in order to test their bravery. Couples holding hands jump over the flames to test their love. If the couple does not succeed it is predicted to split up. Traditionally, children and young unmarried women wear wreaths of wild flowers on their heads to symbolize purity. (Photo by Sergey Dolzhenko/EPA/EFE)

Charistan Hood, 4, eats an ice cream near a picture of former President Barack Obama at the Black-owned Ice Cream Heaven store on Blackout Day 2020 on July 07, 2020 in Miami Gardens, Florida. Supporters of Blackout Day have committed to only spending money at Black-owned businesses to showcase the economic power of the Black community. (Photo by Joe Raedle/Getty Images)

Participants of the 79th edition of the annual Christmas swimming “Coupe de Noel” jump into the Lake Geneva, in Geneva, Switzerland, Sunday, December 17, 2017. More than 2000 men and women swam the 120 meters at the traditional Christmas swimming in Geneva where the water temperature was 6 degrees. (Photo by Martial Trezzini/EPA/EFE/Rex Features/Shutterstock)

An injured young woman is led away after an incident at Parsons Green underground tube station in west London on September 15, 2017. Police and ambulance services said they were responding to an “incident” at Parsons Green underground station in west London on Friday, following media reports of an explosion. A Metro. co. uk reporter at the scene was quoted by the paper as saying that a white container exploded on the train and passengers had suffered facial burns. (Photo by Luke MacGregor/Reuters)

Jerome Holcomb of Birmingham, Ala., posses for a photo atop a longhorn steer at the Fort Worth Stockyards Thursday, March 11, 2021, in Fort Worth, Texas. The mask mandate to prevent the spread of COVID-19 has been cancelled in Texas. Holcomb said he was tired of wearing a face mask so he came to visit Fort Worth after the Alabama governor extended the mask mandate in his home state. (Photo by L.M. Otero/AP Photo)

A couple kisses in a central Barcelona street during the first night without the state of alarm, on 9 May, 2021 in Barcelona, Catalonia, Spain. The state of alarm that the Government decreed for the second time six months ago ended at 00.00 hours this Sunday, May 9. In Catalonia this has led to the fall of the curfew and the perimeter confinement of the Community. (Photo By Lorena Sopena via Getty Images)