Nothing is more important than the Mass, and the Church is bound to keep on celebrating it in and out of season. And that includes war.
Here are some photos of priests celebrating Mass in war zones, or at least out on the field for members of a military.
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You can click on any image to enlarge it.
American soldiers in the bombed Cologne Cathedral (March, 1945)

U.S. Civil War (~1861-1865)

A bombed out chapel in Dommartin, France (WWII?)

[See also: I Knew a Priest Who Could See the Dead]
U.S. 5th Marine Regiment at one of Saddam Hussein’s palaces in Tikrit, Iraq (April, 19th, 2003)

U.K. Royal Air Force in Central Burma (WWII)

111th Naval Construction Battalion in Normandy, France (June, 18th 1944; D-Day + 12)

First Catholic Mass inside a Japanese hanger (WWII?)

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American soldiers from the 80th “Blue Ridge” Division (WWII?)

Soldiers from Alpha Company, 1st Battalion, 17th Infantry Regiment in Badula Qulp, Afghanistan (February 21st, 2010)

65th AAA Batallion at Bolo Point, Okinawa (July 19, 1951)

Sante-Barbe, France (WWI)

St. Paul’s Cathedral in Münster, Germany (1946)

[See also: What a Ceremony for a Nun’s Vows Looked Like in 1962]
A Marine receiving the Eucharist kneeling and on the tongue on Mount Suribachi, Iwo Jima (February or March 1945)

Fr. Kapaun celebrating mass in Korea (~1950-1953)
