South Vietnamese forces escort suspected Viet Cong officer Nguyen Van Lem (also known as Bay Lop) on a Saigon street February 1, 1968, early in the Tet Offensive. Moments later, Lem was executed by Gen. Nguyen Ngoc Loan, chief of the national police. (Photo by Eddie Adams/AP Photo)

In this November 28, 1966 file photo, one of the 10 beagles involved in the first test of the Veterans Administration Hospital in East Orange, N.J. smokes a cigarette through a machine linked to its windpipe by a plastic tube to test any link between smoking and emphysema. (Photo by AP Photo)

A rainbow appears as people enjoy a warm afternoon on a tour boat at Niagara Falls in Ontario, Canada on October 21, 2024. (Photo by Mert Alper Dervis/Anadolu via Getty Images)

The battle by Jose Garcia, US. Category: bird behaviour. A great white heron (Ardea herodias occidentalis) fighting a green snake in the Florida Everglades. The fight lasted for nearly 20 minutes with the heron having to release its prey. (Photo by Jose Garcia/2017 Bird Photographer of the Year Awards)

A skydiver dressed as Santa Claus prepares to leap out of a plane as 155 tandem skydivers set a new Guinness World Record over eight hours, over the Australian city of Wollongong, December 17, 2016. (Photo by Jason Reed/Reuters)

Coast and marine winner: Storm Gull (Lesser black-backed gull), New Haven, East Sussex. (Photo by Craig Denford/British Wildlife Photography Awards)

An Aden civilian crouching in terror as British soldiers threaten him during Arabian demonstrations in Crater. (Photo by Express Newspapers/Getty Images). 1967

A chimp motions for Santa to deliver his gift during Lion Country Safari's annual Christmas with the Chimps on Thursday, December 20, 2012. (Photo by Bruce R. Bennett/The Palm Beach Post)