Scott MacKenzie casts the first line on the opening day of the salmon fishing season on the River Tay at Kenmore in Scotland, Britain January 16, 2017. REUTERS/Russell Cheyne 

U.S. Army soldiers (L-R) Private First Class Trent Pritchartt, Specialist Ben Purvis, and Sergeant William Mackenzie from the 2nd Battalion, 12th Infantry Regiment of the 4th Brigade Combat Team, 4th Infantry Division fire a 120mm mortar at insurgent positions inside of Combat Outpost Nangalam in the Pech River Valley of Afghanistan's Kunar Province July 1, 2012. REUTERS/Lucas Jackson (AFGHANISTAN - Tags: CIVIL UNREST MILITARY) 

Sergeant William Mackenzie from the 2nd Battalion, 12th Infantry Regiment of the 4th Brigade Combat Team, 4th Infantry Division fills out paperwork to report the mortars fired today as he works in a bunker next to a stack of smoke grenades and hand grenades inside of Combat Outpost Nangalam in the Pech River Valley of Afghanistan's Kunar Province July 1, 2012. REUTERS/Lucas Jackson (AFGHANISTAN - Tags: CIVIL UNREST MILITARY) 

U.S. Army soldiers (L-R) Private First Class Trent Pritchartt, Specialist Ben Purvis, and Sergeant William Mackenzie from the 2nd Battalion, 12th Infantry Regiment of the 4th Brigade Combat Team, 4th Infantry Division fire a 120mm mortar at insurgent positions inside of Combat Outpost Nangalam in the Pech River Valley of Afghanistan's Kunar Province July 1, 2012. REUTERS/Lucas Jackson (AFGHANISTAN - Tags: CIVIL UNREST MILITARY) 

U.S. Army soldiers (L-R) Private First Class Trent Pritchartt, Specialist Ben Purvis, and Sergeant William Mackenzie from the 2nd Battalion, 12th Infantry Regiment of the 4th Brigade Combat Team, 4th Infantry Division fire a 120mm mortar at insurgent positions inside of Combat Outpost Nangalam in the Pech River Valley of Afghanistan's Kunar Province July 1, 2012. REUTERS/Lucas Jackson (AFGHANISTAN - Tags: CIVIL UNREST MILITARY) 

U.S. Army soldiers (L-R) Specialist Lance Doan, Private First Class Coty Nolff, Specialist Ben Purvis, Sergeant William Mackenzie, and Staff Sergeant Brandon Durham from the 2nd Battalion, 12th Infantry Regiment of the 4th Brigade Combat Team, 4th Infantry Division check the aim of an 81mm mortar inside of Combat Outpost Nangalam in the Pech River Valley of Afghanistan's Kunar Province June 29, 2012. REUTERS/Lucas Jackson (AFGHANISTAN - Tags: CIVIL UNREST MILITARY) 

Sergeant William Mackenzie from the 2nd Battalion, 12th Infantry Regiment of the 4th Brigade Combat Team, 4th Infantry Division walks out of a bunker inside of Combat Outpost Nangalam in the Pech River Valley of Afghanistan's Kunar Province June 29, 2012. REUTERS/Lucas Jackson (AFGHANISTAN - Tags: CIVIL UNREST MILITARY)