Religious deaths, death pacts, and cult deaths have all been listed as reasons for mass suicide throughout history and most tend to associate group suicide with fanaticism. However, cult and church related suicides are actually somewhat rare historically speaking. War remains one of the most common causes of mass suicides. While incidents like Jonestown resulted in high casualties, some of the deadliest mass suicides were carried out to evade surrender and avoid mistreatment by enemy forces.
There were many mass suicides in World War II, carried in various parts of Germany and Japan. During the reign of the Roman Empire, defeated enemies of Rome often took their own lives rather than being taken as slaves. Every mass suicide in history is a tragedy, however, regardless of the reasons behind it. Survivors of such events can attest to the horrific aftermath and the difficulty of rebuilding, recovering, and moving forward.
Date: Throughout the 1600s
Fatalities: Unknown, likely tens of thousands
Location: Russia - 1600s
Details: In the 1600s, Old Believers - reportedly in the tens of thousands - committed suicide by self-immolation. The suicides were not individual acts but were instead group suicides that usually took place in the monasteries.
The reasons varied, but had to do with the general belief that evil had proved to be a dominant force and the end of the world was close at hand.
Date: April 1945
Location: Throughout Germany
Details: Thousands of people committed suicide during the final days of the Nazi regime to avoid capture, resist defeat, and possibly due to brainwashing and propaganda. Adolf Hitler, Joseph Goebbels, and Heinrich Himmler were among the highest ranking officials who took their own lives. Mass suicides occurred throughout the country, carried out by Nazi supporters as well as their opponents and some victims of the Nazi regime.
Date: February 25, 1337
Details: On February 25, 1337, the Teutonic Knights brought the crusades to the castle of Pilėnai in the Grand Duchy of Lithuania. Defeat was almost certain for Pilénai. Rather than surrendering to the knights, residents committed mass suicide and burned their possessions. An estimated 4,000 people took part in the mass suicide, although due to poor record keeping the number is contested.
However, the event is still widely considered one of the biggest mass suicide in world history.
Date: July, 1944
Fatalities: Unknown, likely in the thousands
Location: Saipan, Japan
Details: In the final days of the Battle of Saipan, thounds of Japanese civilians committed suicide en masse after being ordered to do so by General Saito. He claimed that anyone who ended their own life would receive the same spiritual status as soldiers who died in World War II. This, in addition to the fear of mistreatment by American troops, led to a string of suicides throughout Japan, but especially in the cities of Okinawa and Saipan. Many people jumped off cliffs, particularly one cliff in Saipan that is now known as Suicide Cliff.
Given the chaos and widespread violence in Japan at that time, the cause of death for many civilians and soldiers remains unknown. The death toll is likely around 8,000, but no one is certain how many deaths can be attributed to suicide and how many can be attributed to United States forces.
Source: 1, 2, 3, 4