Documentary filmmaking continues to explore new territory with upcoming films such as Morgan Spurlock’s “POM Wonderful Presents: The Greatest Movie Ever Sold” and Werner Herzog’s “Cave of Forgotten Dreams” – but last week, it lost a voice as well.

Photojournalist Tim Hetherington was killed Wednesday at the age of 41 while covering combat in Misrata, Libya.

But Hetherington leaves behind a great legacy, including co-directing last year’s Academy Award nominee war documentary “Restrepo” and filming 2007’s “The Devil Came on Horseback.”

“Restrepo” airs tonight on National Geographic at 9 p.m. along with a tribute to Hetherington, and students may want to watch some more documentaries in his honor.

The Oracle picks five of the best documentaries in recent years.

“Restrepo”

In 2007, Hetherington and fellow journalist Sebastian Junger shot hundreds of hours of war footage that would eventually become “Restrepo” – a gripping, nonpolitical look at modern warfare.

The film follows a small platoon stationed in Afghanistan’s Korengal Valley. They live in the 15-man outpost Restrepo, named after a dead comrade and called “one of the most dangerous postings in the U.S. military” by CNN.

“Restrepo” shows these soldiers fighting off Taliban forces with machine guns – particularly during the deadly Operation Rock Avalanche.

Yet, it also shows them in human moments like playing guitar and handheld games, and finding brotherhood in the desolate desert surroundings.

“Exit Through the Gift Shop”

Regardless of one’s opinion about the British graffiti artist Banksy, he created a supremely entertaining documentary in 2010’s “Exit Through the Gift Shop.”

The film’s subject is Thierry Guetta, a French shopkeeper and filmmaker who becomes obsessed with street art. He starts eagerly following artists like Shepard Fairey and Banksy and develops his own documentary, “Life Remote Control.”

“Exit Through the Gift Shop” is surprisingly funny in scenes such as Banksy’s reaction to “Life Remote Control,” and some have even questioned whether the documentary is an elaborate prank from Banksy.

The film was nominated alongside “Restrepo” for last year’s Best Documentary Oscar, but lost out to the economic expose, “Inside Job.”

“Dear Zachary: A Letter to a Son About His Father”

Starting off as a simple, home movie-like tribute, “Dear Zachary: A Letter to a Son About His Father” ended up as one of the saddest, most powerful documentaries ever made.

After the murder of his close friend Andrew Bagby, filmmaker Kurt Kuenne starts making a tribute film for Bagby’s still-unborn son Zachary to watch someday when he grows up.

Shirley Turner, Bagby’s ex-girlfriend and suspected murderer, flees to Canada while pregnant with Zachary. Kuenne follows the numerous court and custody battles – and their absolutely heart-wrenching conclusion.

“Dear Zachary” is the rare documentary that led to actual, legislative change. Canada has since introduced the “Zachary Bill,” which lets courts refuse bail to those deemed potentially dangerous to children.

“Grizzly Man”

Filmmaker Werner Herzog is something of an odd soul, being shot mid-interview and saving Joaquin Phoenix from a car crash before mysteriously disappearing, but he detailed an even greater eccentric in 2005’s amazing “Grizzly Man.”

The movie tells the tale of Timothy Treadwell, a man who spent his summers with Alaskan grizzly bears for 13 years before finally being killed and eaten by one in 2003.

Though it would be easy to write Treadwell off as crazy, Herzog creates a deeper portrait with interviews and commentary and Treadwell’s own hours of filmed footage.

One of the film’s best scenes combines both, as Treadwell films a profanity-filled rant against the park service while Herzog’s gentle German voice explains how he’s reached that current point.

“Dark Days”

“Dark Days,” from 2000, documents a community of homeless living in underground New York City tunnels around Penn Station with their makeshift homes.

The film’s director, Marc Singer, spent years with these tunnel dwellers, and the film rarely surfaces above the tunnels except for a few scenes and interviews.

Though its extraordinary subject matter is more than enough to warrant recommendation, “Dark Days” also offers striking black-and-white cinematography and a soundtrack by DJ Shadow.

It even has a somewhat happy ending, which can be sadly rare in today’s documentary filmmaking.