Second Battle of Ypres - AbsoluteAstronomy.com

The Second Battle of Ypres was the first time Germany used poison gas on a large scale on the Western Front

Western Front (World War I)

Following the outbreak of World War I in 1914, the German Army opened the Western Front by first invading Luxembourg and Belgium, then gaining military control of important industrial regions in France. The tide of the advance was dramatically turned with the Battle of the Marne...

in the First World War and the first time a former colonial force (Canadians

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

) pushed back a major European power (Germans) on European soil, which occurred in the battle of St. Julien-Kitcheners' Wood.
The Second Battle of Ypres

Ypres

Ypres is a Belgian municipality located in the Flemish province of West Flanders. The municipality comprises the city of Ypres and the villages of Boezinge, Brielen, Dikkebus, Elverdinge, Hollebeke, Sint-Jan, Vlamertinge, Voormezele, Zillebeke, and Zuidschote...

consisted of four separate engagements:

The Battle of Gravenstafel: Thursday 22 April – Friday 23 April 1915
The Battle of Saint Julien: Saturday 24 April – 4 May 1915.
The Battle of Frezenberg: 8–13 May 1915
The Battle of Bellewaarde: 24–25 May 1915

The scene of the battles was the Ypres salient

Ypres Salient

The Ypres Salient is the area around Ypres in Belgium which was the scene of some of the biggest battles in World War I.In military terms, a salient is a battlefield feature that projects into enemy territory. Therefore, the salient is surrounded by the enemy on three sides, making the troops...

on the Western Front, where the Allied line which followed the canal bulged eastward around the town of Ypres

Ypres

, Belgium.