Germany, Business couple making love under desk. (Photo by Roman Maerzinger/Getty Images)

A woman dressed for la “La Diablada” festival walks down a road in Pillaro, Ecuador, Friday, January 6, 2017. Local legend holds that anyone who adopts a costume for the celebration and wears it at the event six years in a row will have good luck. (Photo by Dolores Ochoa/AP Photo)

The nearly four-week-old Tapir cub bathes on June 28, 2016 in Gondwanaland at the zoo in Leipzig, Saxony. (Photo by Jan Woitas/DPA)

A life-size robot named “Mark 1”, built by product and graphic designer Ricky Ma, 42, is seen in Hong Kong, China March 31, 2016. Ma, a robot enthusiast, spent a year-and-a half and more than HK$400,000 ($51,000) to create the humanoid robot, which is modelled after a Hollywood star, to fulfil his childhood dream. The eyes of the robot include face and color tracking functions. (Photo by Bobby Yip/Reuters)

Two elderly men smoking pipes of opium on a terrace in Korea. (Photo by Bert Hardy/Picture Post/Getty Images). August 1950

Television actress Catherine Fuller visits Trafalgar Square in London and feeds the famous pigeons. (Photo by Harry Kerr/BIPs/Getty Images). 26th June 1956

Thor, Virginia Tech College of Engineering, Robotics and Mechanisms Laboratory, tries to connect the hose to a firehose connection during the hose task at the Homestead-Miami Speedway, Friday, December 20, 2013, in Homestead, Fla. (Photo by Alan Diaz/AP Photo)

Four-man bicycle is powered by five chains and has brakes on both its wheels, 1948. The bike was built by Art Rothschild (top position) who broke three ribs while learning how to ride it. (Photo by Wallace Kirkland/Time & Life Pictures)