A young YPJ recruit (in pink) arrives to the training base for her first day in training near Derek City, Syria. The YPJ schedule is demanding and requires discipline – new soldiers in training get about 6 hours of sleep a night and wake up at 4 AM to begin exercising; afterwards, their day consists of a full schedule of drills and classroom lessons. Before joining the YPJ many of the girls had never participated in physical activity or sports before. (Photo by Erin Trieb/NBC News)

An air raid drill at Seattle College caught students William Bates, left, and Edna Mae Farrell, right, while they were eating their lunch in the school café, but they simply took shelter under the table and continued eating in Seattle, Washington, March 17, 1942. Air raid wardens said 350 students left their classrooms and assembled in shelters within one minute in first at the college. (Photo by AP Photo)

RAF volunteers from stations across the UK, who will be acting as the lining party during the Royal Wedding, practice drills in the Parade square at RAF Holton on April 26, 2011 in Aylesbury, England. The members will make up the Queen's Colour Squadron, and will be lining the route between Buckingham Palace and Westminster Abbey during the wedding of Prince William and Catherine Middleton on April 29, 2011. (Photo by Dan Kitwood/Getty Images)

One morning, this Redditor woke up to his front porch completely riddled with holes. It looked like some gang members spewed buckshot at his doorstep during a drive-by. These holes were made by acorn woodpeckers. The little birds created their own granaries or “acorn trees” to store their food. They do so by drilling holes into whatever they can, sometimes resulting in this kind of damage.

South Korean military soldiers take part in the South Korea and U.S. joint military exercise to commemorate the 63th Korea Armed Forces Day at the Seungjin firing drill ground on September 30, 2011 in Pocheon, South Korea. The exercise is intended to prepare the South Korean defence force for any potential action from North Korea. (Photo by Chung Sung-Jun/Getty Images)

Slovenian artist Franc Grom, aged 72, makes unbelievably intricate egg sculptures using just a tiny electric drill and enormous patience. According to National Geographic, when finished, each egg contains approximately 2,500 to 3,500 holes. While Slovene artisans usually paint their eggs using a technique called drsanka by lightly scratching intricate patterns into the surfaces of colored eggs, carving them was solely Grom’s idea.

Students receive a group punishment during a military-style close-order drill class at the Qide Education Center in Beijing February 19, 2014. The Qide Education Center is a military-style boot camp which offers treatment for internet addiction. As growing numbers of young people in China immerse themselves in the cyber world, spending hours playing games online, worried parents are increasingly turning to boot camps to crush addiction. Military-style boot camps, designed to wean young people off their addiction to the internet, number as many as 250 in China alone. (Photo by Kim Kyung-Hoon/Reuters)

In this undated photo released Tuesday April 13, 2021, by Russian Defense Ministry Press Service, A Tu-160 strategic bomber of the Russian air force is shown on a training mission somewhere in Russia. Russian Defense Minister Sergei Shoigu on Tuesday described a massive military buildup in western Russia as part of drills intended to check the armed forces' readiness amid the threats posed by NATO. (Photo by Vadim Savitsky/Russian Defense Ministry Press Service via AP Photo)