Websites like IMDb and Rotten Tomatoes are a great help when trying to decide what movie to watch, as they make things easier for everybody by assigning a certain grade to every film or show. Such rankings are far from perfect, and certainly not definitive, but they are helpful. Metacritic is one of the most popular among these review aggregator sites, and they don't just score movies and TV shows, but video games and music albums too. A "Metascore" of 100 is a rarity, and only 8 films currently exist that have been honored with this score.

RELATED: The Best Picture Winners Of The 2010s, Ranked According To Metacritic

All except one of these 8 are old classics, but thanks to advances in technology it is now easier than ever to pick them up for a watch. Most are available for direct streaming (while some aren't), but whatever the case, if their perfect scores say anything, it is that they're a must-watch.

Notorious (1946) - FlixFling

Cary Grant and Ingrid Bergman intimately embracing in Alfred Hitchcock's Notorious

The fact that there are only 8 films in existence with a 100 Metacritic score, and 3 of them were directed by Alfred Hitchcock, says all there is to say about him.

A classic spy-noir film that precedes the likes of James Bond by decades, this movie revolves around a government agent T.R. Devlin working with the daughter of a German war criminal to infiltrate a Nazi organization. The two fall in love, and trouble of the romantic nature arises when she is tasked to seduce a former lover and current head of the Nazi group. FlixFling and Indieflix are well-known streaming sites, but they're the only places that have this film in their library.

Vertigo (1958) - iTunes/Youtube/Google Play Movies

James Stewart with a terrified expression in the poster of Alfred Hitchcock's Vertigo

In one of the most acclaimed films of his legendary career, James Stewart plays a police detective who, due to an incident in the line of work, starts suffering from a serious case of acrophobia (fear of heights) and vertigo. Forced into retirement, he takes up a job offered by a former associate Gavin Elster, who believes his wife's strange behaviors warrant a closer investigation.

RELATED: 10 Best Quotes From Alfred Hitchcock Movies

What begins as a simple task of following a woman around town expands into something much more sinister, involving a century-old suicide case and an overly intricate murder plot. Although it can't be streamed currently, renting or buying is still an option from iTunes or Google Play.

Three Colors: Red (1994) - HBO Max

Irène Jacob as Valentine Dussaut blowing a bubble gum with a red background behind her

Polish director Krzysztof Kieślowski's Three Colors deals with symbolism and underlying themes in a way few films do. Each film in the trilogy is named after a color, Blue, White, and Red, and these colors are a direct reference to the colors of the French flag. The ambiguous motifs present in the films are a part of the experience, and each film is based on concepts like liberty, equality, and fraternity, which in turn comes from the national motto of France.

The third entry in the trilogy, Red, is the highest-rated one and also the last film director Kieślowski made. The entire trilogy can be streamed on HBO Max.

Boyhood (2014) - AMC+

Ellar Coltrane as Mason Evans Jr. in Boyhood standing in an open hilly area wearing a black shirt

Sometimes the behind the scenes story of how a film got made is even more amazing than the film itself, which is the case with Boyhood. Instead of going the normal route of hiring different actors of different ages to portray a singular character's growth over the years, director and writer Richard Linklater instead chose to capture the life of the same actor over the course of 12 years.

RELATED: 12 Years In The Making: 10 Behind-The-Scenes Facts About Boyhood

The film starts in 2002, with a six-year-old actor Ellar Coltrane playing a child of the same age, and from there follows his life over a 12 year period until he is in college, exploring all the bittersweet things in between.

Casablanca (1943) - HBO Max

poster for Casablanca featuring Humphrey Bogart, Ingrid Bergman and Paul Henreid

Nothing defines the Golden Age of Hollywood better than romantic classics like CasablancaWorld War II was a difficult and complicated time for many due to reasons that need no explanation, and Casablanca isn't just set in that time period, but was filmed and released while the war was still raging.

It revolves around a man named Rick Blaine who owns a business in the North-African city of Casablanca and is approached by his former lover Ilsa Lund to help them escape to the USA, as they are being hunted down by the Nazi party.

Rear Window (1954) - iTunes/YouTube/Amazon Video/ Google Play Movies

Jeff sitting in a wheelchair with Lisa lying in front of him in Rear Window

In their second collaboration, James Stewart and Alfred Hitchcock tell the story of L.B. Jefferies, a professional photographer who is stuck within his small apartment because of a broken leg. As this was before the days of Netflix and video games, he decides to spend all this unwanted free time by observing the activities of his neighbors through his window with a camera lens.

RELATED: Singin' In The Rain & 9 Other Best Hollywood Movies Of The 1950s

His keen observational skills soon bring him to the conclusion that one of them is a murderer. Like many films of its age it, isn't available for streaming, but can be rented/bought from a variety of sources such as iTunes, YouTube, and Amazon Video.

The Godfather (1972) - Paramount+

iconic scene from The Godfather depicting Bonasera whispering into the ears of Vito Corleone

The pinnacle of the 70s surge of mafia movies, The Godfather would go on to influence the crime-drama genre in a way only the greatest films ever made have. Marlon Brando portrays one of the most dramatically epic characters ever as Vito Corleone, a man of one-liners that are each more iconic than the other.

Directed by Francis Ford Coppola, the film is based on the book of the same name written by author Mario Puzo. The only film capable of matching the standards set by The Godfather is the sequel,  The Godfather Part II, which became the first sequel ever to win a Best Picture Oscar, and debates about which film is better are continuous.

Citizen Kane (1941) - HBO Max

Charles Foster Kane in Citizen Kane standing in front of a huge poster of himself

Orson Welles wrote, directed, produced, and played the lead part in Citizen Kane, and the fact that it was the first feature film of his career just makes it all more impressive. The "greatest movie ever made" is too ambitious a title, but one that has been used to refer to Citizen Kane by many.

Its cinematography, storytelling, and everything else influenced how movies were made to a degree that is difficult to quantify, even more so from a modern-day point of view. Until recently it was one of the few films with a solid 100% rating on Rotten Tomatoes.

NEXT: Seven Samurai & 9 Other Classic Foreign Films On HBO Max, Ranked By IMDb