May is military appreciation month — a time to reflect with gratitude on the men and women who have served this country. And there was no perhaps no more necessary time in American history for citizens to answer the call to service than World War II.

Numerous documentaries have ventured to convey the seemingly insurmountable odds confronted by ground, air and naval forces, and the immense sacrifices that resulted.

As such, we compiled a list of five comprehensive World World II documentaries that best tell these harrowing stories.

World War II in HD

Released by the History Channel in 2009, this 10-episode series narrated by Gary Sinise (”Forrest Gump”) uses stunning footage from both the European and Pacific fronts, much of which was shot in color, to illustrate the horrors and triumphs of war.

The producers sourced first-hand stories from journalists, medics and soldiers, and used voice overs by professional actors to bring them to life.

Inside World War II

Released in 2012, this three-part documentary from National Geographic features personal stories of World War II from troops who lived it. According to its synopsis, the series “takes an intimate look at personal wartime experiences from the perspective of a wide array of veterans and citizens who endured … bloody conflicts day by day, hour by hour, and second by second.”

Episodes feature both black-and-white and color footage that move chronologically though the war’s defining moments.

World War II: The Last Heroes

This six-part series, which focuses on the ordinary boys who became heroes, begins with D-Day and ends at the war’s conclusion. The crux of this particular documentary is a story of war as told by its foot soldiers — rather than through a lens of historians or high-ranking decision makers.

The series is currently available to view on Amazon Prime.

World War 2: The Complete History

“The Complete History” is a slightly older series designed to appeal to the well-versed history and military buffs interested in oft overlooked details of the conflict.

Produced in 2000 and narrated by Peter Dickson (”Britain’s Got Talent”), the documentary begins with pre-WWII discussions surrounding the Treaty of Versailles and the Japanese invasion of Manchuria and concludes with the Nuremberg trials and the Cold War.

Apocalypse: The Second World War

This six-part French documentary is perhaps one of the best international films on the conflict. U.S. viewers, meanwhile, can enjoy a National Geographic-treated version narrated by Martin Sheen. The series can be easily digested by a WWII novice wanting to understand the high points of the war.

The documentary comprises footage — shot by regular citizens, journalists, and troops on the ground — that has been colorized and digitally remastered.

Originally published by Military Times, our sister publication.