Tactics reminiscent of the early American frontier days are now being used in Vietnam. Lieutenant Commander Donald D. Sheppard, UBN, of Coronado, California, aims a flaming arrow at a bamboo hut concealing a fortified Viet Cong bunker on the banks of the Bassac River, Vietnam on December 8, 1967. (Photo by AP Photo)

Western lowland gorilla Kijivu holds her newborn baby at the Prague Zoo in the Czech Republic. (Photo by Isifa/Getty Images)

Nazi dictator Adolf Hitler greets supporters at a May Day gathering in the Olympic Stadium, Berlin. (Photo by Keystone). 1st May 1938

2016 Rio Olympics, Judo, Final, Women, 48 kg Bronze Medal Contests, Carioca Arena 2, Rio de Janeiro, Brazil on August 6, 2016. Otgontsetseg Galbadrakh (KAZ) of Kazakhstan and Dayaris Mestre Alvarez (CUB) of Cuba react. (Photo by Kai Pfaffenbach/Reuters)

2016 Rio Olympics, Athletics, Final, Women's 200m Final, Olympic Stadium, Rio de Janeiro, Brazil on August 17, 2016. Photographers take pictures of Elaine Thompson (JAM) of Jamaica after she won the gold. (Photo by Gonzalo Fuentes/Reuters)

Troops of the Interior Ministry take part in a parade during a ceremony marking the Iraqi Police Day at a police academy in Baghdad January 9, 2016. (Photo by Khalid al Mousily/Reuters)

Faithful jump into the waters of Fasilides Bath as part of a ceremony in which the waters are blessed by the priest of Ethiopian Orthodox Tewahedo church during the second day of Timket in Gondar, Ethiopia, January 20, 2016. “Timket”, the greatest Ethiopian festival of the year is to commemorate Jesus Christ's baptism in the Jordan River by John the Baptist. (Photo by Tiksa Negeri/Reuters)

An Indian Army soldier marches next to a tableau during the Republic Day parade in New Delhi, India, January 26, 2016. India celebrated its Republic Day Tuesday, highlighted by a march by different branches of the military as well as a display of arms and missiles. (Photo by Adnan Abidi/Reuters)