An American soldier walks ahead of an MKIV (Mark IV) British-made tank, circa 1918. (Photo by Hulton Archive/Getty Images)

This handout picture taken and released by Thai Royal Household Bureau on December 12, 2019 shows Thailand's Princess Bajrakitiyabha (L) and Princess Sirivannavari sit in their barge during the Royal Barge procession in Bangkok. The Royal barge procession is the final event of the coronation of Thailand’s King Maha Vajiralongkorn. (Photo by Thai Royal Household Bureau via AFP Photo/Handout)

Medical workers wearing gear enter a residential area placed under the enhanced movement control order (EMCO) due to a drastic increase in the number of COVID-19 cases recorded in Sunway, outskirt of Kuala Lumpur, Malaysia, Friday, July 2, 2021. Malaysia starts to further tighten movement curbs and impose a curfew in most areas in its richest state Selangor and parts of Kuala Lumpur, where coronavirus cases remain high despite a national lockdown last month. (Photo by Vincent Thian/AP Photo)

Flames from the Erskine Fire engulf a trailer near Weldon, California, U.S. June 24, 2016. (Photo by Noah Berger/Reuters)

A woman tries to take selfie photos in front of a photo spot featuring Christmas season scene and masks at Tokyo Mask Land, a face-mask theme exhibition and its speciality shop, amid the coronavirus disease (COVID-19) outbreak, in Yokohama, Japan on December 1, 2020. (Photo by Issei Kato/Reuters)

Macro or Micro? Scientists’ pictures baffle our sense of scale. It began when Stephen Young, a geography professor at Salem State University in Massachusetts, tricked his biologist colleague Paul Kelly into thinking a satellite image was one of his electron microscope scans. Can you guess whether they are close-up or very far away? (Photo by Paul Kelly)