The waning moon sets behind leafless sumac trees on a crisp, clear morning, Thursday, December 15, 2016, in Portland, Maine. Much of the northern Mid-Atlantic and Northeast will stay cold for the next couple of days as the arctic air remains stuck over the northern Appalachians, the National Weather Service said. (Photo by Robert F. Bukaty/AP Photo)

A reveller is tossed into the air as they celebrate the Holi spring festival in Kathmandu on March 12, 2017. The “Holi” festival of colours is a riotous celebration of the coming of spring and falls on the day after the full moon in early March every year. (Photo by Prakash Mathema/AFP Photo)

Entertainment One is attempting to set the Guinness World Record for the longest chain of brides in one location at HMV, Oxford Street on March 11, 2012 in London, United Kingdom. The event was held to celebrate to celebrate the DVD release of The Twilight Saga: Twilight Breaking Dawn Part 1 (Photo by Dave J. Hogan/Getty Images)

Joe Deedon, president of TAC ONE Consulting, demonstrates searching for a shooter in a middle school during an Active Shooter Response course offered by TAC ONE in Denver April 2, 2016. According to TAC ONE, the course, which is offered for the first time to concealed weapons permit carrying civilians, is designed at preparing people to effectively save lives prior to the arrival of law enforcement at an active shooter incident. (Photo by Rick Wilking/Reuters)

Tajammu Al-Ezza brigade fighters react while firing a Grad shell towards forces of Syria's President Bashar Al-Assad stationed in Salhab village, Hama countryside, May 7, 2015. (Photo by Mohamad Bayoush/Reuters)

A tractor trailer drives through flash flood waters that overran Skunk Creek, Tuesday, August 19, 2014, in northwestern Phoenix. Flooding from heavy rain in the Phoenix area has forced authorities to close several major roads, including a portion of Interstate 17 about 25 miles north of the city. (Photo by Matt York/AP Photo)

Iranian Arabs who are members of the paramilitary Basij force march in a military parade marking the 35th anniversary of Iraq's 1980 invasion of Iran, in front of the shrine of late revolutionary founder Ayatollah Khomeini, just outside Tehran, Iran, Tuesday, September 22, 2015. (Photo by Vahid Salemi/AP Photo)

Five hundred replicas of the Stormtrooper characters from "Star Wars" are placed on the steps at the Juyongguan section of the Great Wall of China during a promotional event for "Star Wars: The Force Awakens" film, on the outskirts of Beijing, China, October 20, 2015. (Photo by Jason Lee/Reuters)