Portrait of a police officer in a gas mask as he stands with a riot gun in his hand and spare tear gas cartridges in his shirt during the 'Honor America Day Smoke-In' thrown by marijuana activists to protest the official 'Honor America Day' ceremonies being held at the Lincoln Memorial, Washington, DC, July 4, 1970. He has a mini American flag in one pocket and, perhaps ironically, a pack of cigarettes in the other. (Photo by David Fenton/Getty Images)