There are many film fans who consider the 1970s to be the greatest era in American filmmaking. So many movies that are considered among the greatest ever made have come out of this decade. The 1970s are also known for the emergence of a gritty and grounded approach to cinema.

RELATED: The 5 Best (& 5 Worst) '70s Crime Movies

With filmmakers like Martin Scorsese, William Friedkin, and Francis Ford Coppola contributing to the genre, crime films became one of the biggest draws at the box office. But even with all the acclaim, some great films fell through the cracks while other celebrated films failed to hold up years later.

Underrated: The Conversation (1974)

Though Francis Ford Coppola made The Godfather films and Apocalypse Now, there are some who think The Conversation is his true masterpiece. The film stars Gene Hackman as a surveillance expert living a lonely life until he is drawn into a murder conspiracy.

The Conversation was nominated for Best Picture, but it often gets lost in the shuffle, especially when compared to Coppola's other work. Yet it remains a tense and brilliant crime film that lingers long after the credits roll.

Overrated: The French Connection (1971)

Hackman won his first Oscar for his intense role as Popeye Doyle in the cop drama The French Connection. Loosely based on real events, Doyle and his partner work the streets of New York City with their unorthodox tactics to uncover a drug-smuggling operation.

RELATED: 10 Best Lines From Cult Classic Cop Films

The French Connection won a handful of Oscars, including Best Picture, and is considered a masterpiece of the genre. There are aspects of the film, such as the epic car chase, that still holds up extremely well. But Doyle's antihero persona now feels racist and corrupt, making him a tough protagonist to root for.

Underrated: Thunderbolt And Lightfoot (1974)

Thunderbolt and Lightfoot

The pairing of Clint Eastwood and Jeff Bridges in a buddy crime movie should have made for a popular film, but Thunderbolt and Lightfoot has been forgotten over the years. The two leads star as criminals who team up to pull off an ambitious heist.

The movie isn't one of the more popular in either of the actors' filmographies, but it features winning performances from both. Their chemistry is perfect, the humor is fantastic and the heist is thrilling.

Overrated: The Getaway (1972)

Steve McQueen is one of the icons of the crime genre and The Getaway stands as one of his most beloved films. Based on the Jim Thompson novel, it follows a man and woman who pull off a heist and must then make it to freedom with the law chasing them.

The movie is a fun ride and there's really not too much to dislike overall. But the reason it remains a disappointment is that it ignores the novel's much more intriguing and satisfying epilogue.

Underrated: The Friends Of Eddie Coyle (1973)

Eddie at a hockey game in The Friends of Eddie Coyle

The crime genre can often focus on the big-shot gangster at the top of the pyramid, but The Friends of Eddie Coyle proves that there are interesting stories to be told among the blue-collar members of organized crime.

RELATED: 10 True Crime Books Too Twisted To Be Made Into Films

Robert Mitchum plays the titular character, a low-level thug who is facing a lengthy prison sentence and questions his loyalty to those he works for. The Friends of Eddie Coyle is a smaller, quieter crime film brilliantly told and giving an absorbing glimpse at a part of this world that is rarely seen.

Overrated: Soylent Green (1973)

Thorn looking at the line of Soylent Green

Though set in the future, Soylent Green is as much a crime film as it is a sci-fi film. Charlton Heston plays a detective living in a society that is overcrowded to the point that there is a massive food shortage. He begins investigating a murder that could be linked to a large food manufacturer.

The film has one of the most iconic twists in film history which is probably more famous than the movie itself. Without the impact of that twist, the movie is minimally interesting in its depiction of the future.

Underrated: The Driver (1978)

Though it is not very well-known among modern audiences, the crime film The Driver has been a clear inspiration for such modern hits as Drive and Baby Driver. Ryan O'Neal plays a reserved getaway driver who is hunted by a determined detective, played by Bruce Dern.

The low-key and stylish nature of The Driver sets it apart from bigger films in the genre and it really comes alive during its fun action sequences. O'Neal makes for a fantastic quiet antihero while Dern steals the show with a wild performance.

Overrated: Straw Dogs (1971)

Dustin Hoffman in Straw Dogs

Dustin Hoffman doesn't seem like the type of guy to be in a hard-hitting crime film, but Straw Dogs used that persona to tell this violent tale. Hoffman plays a big city man who moves to an English rural community where they are soon harassed by some ruthless locals.

RELATED: The 5 Best (And 5 Worst) '80s Crime Movies

The movie comes from the great action filmmaker Sam Peckinpah and seems to be a commentary on violence, but it gets lost among all the gruesomeness. There are some truly disturbing scenes that feel almost irresponsible on the part of the filmmaker.

Underrated: The Taking Of Pelham One Two Three (1974)

Walter Matthau in The Taking of Pelham One Two Three

It's a shame that more people aren't aware of The Taking of Pelham One Two Three as it is one of the most entertaining crime films audiences are likely to see. It follows a group of criminals who hijack a New York City subway car and its passengers for ransom.

The film takes a very intense crime premise and inserts it into the mad world of 1970s New York City. This injects a great sense of humor into the story with a ton of hilarious characters. It also includes an ending guaranteed to put a smile on your face.

Overrated: Dirty Harry (1971)

Harry Callahan, as played by Clint Eastwood, is one of the most iconic movie cops of all time. Dirty Harry kickstarted the franchise about this San Francisco detective who plays by his own rules as he investigates a serial killer on the loose.

Whatever charm the character of Harry Callahan had is long gone when viewing these movies today. His rebel attitude comes off as a cop who abuses his power, uses excessive force, and has no regard for the actual law. Such a character in a fairly dull story makes for an unappealing thriller.

NEXT: Clint Eastwood: 5 Best & 5 Worst Movies, According To Rotten Tomatoes