Guns, demons, metal music, and huge guts. What would id Software’s legendary series be without them? The DOOM games have rightfully earned a reputation as one of the all-time best first-person shooters ever. The graphics and platforms may change over the years, but blasting demons on other worlds will always be fun.

Looking back on all the different levels in DOOM, the FPS franchise has certainly taken players to some strange places. From flat sprites of E1M1 to massive HD realms, so much demonic blood has been spilled across many locations. So, maybe it’s time to take a break from decorating the environment in demon gore and look back on the unique areas from DOOM.

The Doom Slayer has gone to Hell so many times he’s practically a veteran resident. If it’s not Hell, it’s another world that’s fallen to ruin and become riddled with blood, death, and devastation. So, imagine fans' surprise when they first arrived at Urdak during the events of DOOM Eternal.

Pure, clean, alien, and holy. Urdak might be the closest to Heaven that DOOM players will ever see in this franchise. Created by The Father, ruled by the Khan Maykr, Urdak was one of the few realms free of demonic influence, at least until the Icon of Sin awakens. Then the holy realm falls apart and it’s back to killing demons as usual. Well, at least it was pretty for the first few moments.

When they were first introduced in DOOM (2016), the Sentinels were a race of mystery and intrigue—warriors who fought alongside the Doom Slayer against the demonic forces. Unfortunately, players had to wait until DOOM Eternal to learn more about this fascinating culture.

In his quest to save Earth from invasion, the Doom Slayer makes several trips to the Sentinel world of Argent D’Nur. Despite the medieval decorum, the Sentinels are an advanced society, as their weapons and armor have shown. It was on Argent D’Nur where players encountered King Novik, were given a warrior’s welcome by Sentinel warriors, and battled the Gladiator in the coliseum. If the Doom Slayer weren’t so busy saving humanity, Argent D’Nur would make for a good retirement location.

Every hero needs a place to call home. Batman has the Batcave. Superman has the Fortress of Solitude. The Doom Slayer has the Fortress of Doom. Out in space, the station orbits the Earth, giving players a complete view of the demonic presence as they plan their next move in saving the world.

The Fortress of Doom was the first hub location in the DOOM series. Here, the space station acts as both a fortress and a Man Cave. Because when the Doom Slayer isn’t using the onboard teleporter to portal to the next mission, he’s usually hanging out listening to music, checking his collectibles, unlocking secrets and upgrades, training, or just reminiscing about Daisy.

It doesn’t matter what planet or realm the UAC settles on—their activities are always going to end in a demonic disaster. Every terrible thing that has happened in the DOOM franchise can almost always be traced back to the UAC. Inhuman experiments, unholy rituals, unsafe working conditions, just about every UAC lab or facility would make any OSHA inspector cry.

The only good thing to come out of the UAC’s research was giving the Doom Slayer access to their portal technology and BFG weaponry. Since the first game, every base carrying the UAC logo has suffered a fatal disaster that resulted in loss of life and a demon infestation. At the very least, each base comes stocked with enough guns and ammo to make the Doom Slayer’s job easier.

It’s tragic to consider that the only times the Doom Slayer’s been on his home planet is when it's under demonic invasion. Besides annihilating every last demon until nothing is left, the Doom Slayer’s main goal has been ensuring the forces of Hell never reach Earth. As the events of DOOM II and Eternal have shown, even with all of humanity’s advancements, they’re powerless against the unholy invaders.

Tragic as it may sound, some of the best levels in the series have taken place on Earth. Instead of an alien world or foreign realm, you’re battling in an apocalyptic setting through places that seem familiar—destroyed buildings, burning homes, and ruined streets overrun with demons that need removing. But what separates DOOM’s apocalypse from something like Fallout is that when the Doom Slayer prevails, Earth’s apocalypse will be over.

Mars, Hell, and Earth might be the more notable locations in the franchise, but what some players forget is that it was on Phobos, one of Mars’ moons, where the DOOM games truly started. Named after the Greek god of fear and panic--a rather fitting name at that--it was Phobos where the iconic E1M1 level of the first game took place.

Starting with nothing but a pistol, a fledgling Doom Slayer has his first encounter with the demons of Hell, facing Zombies and Imps. Fighting from facility to facility, the Slayer would eventually make it off Phobos and wouldn’t return until years later. In DOOM Eternal, Phobos would once again suffer another demonic invasion, and the Doom Slayer would return to his old stomping grounds to make use of the facility’s massive weapon: the BFG-10000.

The iconic Red Planet. It’s funny how Mars has long been associated with the franchise, but in reality, it wasn’t until DOOM 64 when the games were directly set on the world. Since then, countless invasions have been fought here across the sequels. Though most of DOOM 3 takes place on Mars, the action is spent indoors--that, and it was too dark to see anything either.

When fans think of Mars, they think of DOOM (2016), when the Doom Slayer first awoke and restarted his campaign of ripping and tearing. From the desolate surface to the bloodstained facilities, it was on Mars where the DOOM franchise was rebooted. It’s one of the reasons that the planet is so well remembered. Then, players showed their love by blowing a hole into the surface of Mars during one of the most iconic moments in DOOM Eternal. Good times.

When it comes to Hell, few games have the guts to take players into the underworld, but DOOM is the only franchise where telling someone to go to Hell is considered a compliment. Because that’s the one place players can’t wait to visit when playing. While its appearance changes in every release--from fire and brimstone to guts and gore—Hell will always remain an integral part of the games.

DOOM’s version of Hell is like a horror story. It’s dark, appalling, and messy, but YOU’RE the monster as you plummet into a world of suffering to make the demons suffer. It’s a warped outlook, but when you’re the guardian of humanity, one who’s bent on wiping out all demons from existence, you might as well take the fight to the source. Just remember to pack plenty of ammo.