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)

In this Monday, March 18, 2019 photo, a street artist performs in Caracas, Venezuela. Venezuelans are facing a severe economic and political crisis as President Nicolas Maduro has remained in power despite heavy pressure from the United States and other countries arrayed against him, managing to retain the loyalty of most of Venezuela's military leaders. (Photo by Natacha Pisarenko/AP Photo)

In this handout image provided by the National Oceanic and Atmospheric Administration (NOAA), model runs from the Center for Tsunami Research at the NOAA Pacific Marine Environmental Laboratory show the expected wave heights of the tsunami as it travels across the Pacific basin March 11, 2011. The largest wave heights are expected near the earthquake epicenter, off Japan. The wave will decrease in height as it travels across the deep Pacific but grow taller as it nears coastal areas. In general, as the energy of the wave decreases with distance, the near shore heights will also decrease (e.g., coastal Hawaii will not expect heights of that encountered in coastal Japan). (Photo by NOAA via Getty Images)

Baby giraffe of Niger (Giraffa Camelopardalis) “Kenai” (R), born on August 25, 2016, kisses his mother “Dioni” on August 31, 2016 at the zoo of La Fleche, northwestern France. (Photo by Jean-Francois Monier/AFP Photo)

“Kids of Sapa”. Four little beautiful Hmong girls from Lao Chai Village, near Sapa, Vietnam. (Photo and caption by Felipe Hanower/National Geographic Traveler Photo Contest)

Tara West signals to her partner Natalie Cook during the Bronze final match during the Australian Beach Volleyball Championships at Glenelg Beach on March 13, 2011 in Adelaide, Australia.

Indian Hindu devotees wait to take part in an event to mark Pongal in Mumbai on January 15, 2016. Pongal, which coincides with the Hindu festival Makara Sankranthi, is a thanksgiving and harvest celebrated throughout India and specifically by those from the Indian state of Tamil Nadu. (Photo by Indranil Mukherjee/AFP Photo)

Poland's Dawid Kubacki soars through the air during the men's FIS Ski Jumping World Cup competition in Engelberg, central Switzerland, on December 20, 2014. (Photo by Fabrice Coffrini/AFP Photo)