A Yemeni soldier, pictured through a vehicle's windscreen, which was damaged by a bullet, gestures out of the window, in Marib, Yemen October 15, 2015. Marib is a city that is heavily armed even by the standards of Yemen, where the ready availability of weapons helped start civil war and is now preventing anyone coming out on top. Yemenis often say there are three guns for every person, a boast that has become an urgent concern in a country where the United Nations says the humanitarian situation is "critical". (Photo by Angus McDowall/Reuters)

An ethnic Kayaw couple Mu Htoo and her husband Htaw Eili rest at their home at Htaykho village in the Kayah state, Myanmar September 12, 2015. With about 30,000 members, the Kayaw are one of the smallest ethnic minorities among Myanmar's 135 groups. Their village has for decades been off-limits, as armed rebels fought the military before a recent ceasefire stopped the bloody conflict here. The rebels in the area have put down their guns and taken to the hills to grow rice and corn, but slash-and-burn cultivation methods mean they struggle to find new places to farm. (Photo by Soe Zeya Tun/Reuters)

A female participant armed with a bottle of ketchup attacks in the annual Vegetable Battle in Kreuzberg district near Oberbaumbruecke Bridge on August 28, 2011 in Berlin, Germany. The event pits Kreuzberg district residents againts Friedrichshain district residents for control of the Oberbaumbruecke, and the two sides pelt each other with rotten vegetables, other foods, ketchup, water guns and styrofoam bats until one side has pushed the other from the bridge. The event had originally been cancelled for today, but so many participants showed up anyway and began battling on the Kreuzberg side, where the situation escalated and began to threaten traffic, that police relented and let them later battle it out on the bridge. Kreuzberg claimed victory. (Photo by Sean Gallup/Getty Images)

These black-and-white photos are taken from the new book “Armoured Warfare in the First World War 1916 – 1918” by Anthony Tucker-Jones and published by Pen & Sword Military. Here: British troops hitch a ride on a Mark IV after the massed tank fleet spearheading attack at Cambrai on November 20, 1917. (Photo by Anthony Tucker-Jones/Mediadrumworld.com)

Mounted cop in action on Tremont Street in Boston, Massachusetts, 1920 – 1929 (approximate). (Photo by Leslie Jones)

Hannah Rice, 18, jumps from a stump after posing for a photograph next to a large bust of President Franklin D. Roosevelt while touring busts of U.S. presidents in Williamsburg, Va. on March 30, 2019. The statues were once part of an attraction called Presidents Park, which has since closed. (Photo by Matt McClain/The Washington Post)

An armoured vehicle surrounded by Chicago cops at the time of the American depression, 1933. (Photo by Rolls Press/Popperfoto/Getty Images)

In this May 24, 2017, photo, DriveTanks.com customers drive on a tank course at Ox Ranch in Uvalde, Texas. The ranch is a free-roaming range filled with exotic animals, some to hunt, and home to DriveTanks.com, where tourists pay to transport themselves into another era and another life. (Photo by Michael Ciaglo/Houston Chronicle via AP Photo)