This Way to Certain Death

Our adventurer is working his way through the dark tomb of King Nohatsuput, but he is not worried about the "curse", nor the many Death Traps, nor Nohatsuput's Mummy rising again to strangle him. Nope, no worries at all because he bought a special talisman from the local villagers. But wait... the bones of many previous adventurers all lie along this path... all with the same familiar talisman...

This trope describes the instance when a character (or perhaps just the audience) realises this is a dangerous area, because many other people in the same circumstances have left evidence of their demise.

In several instances, this trope becomes a Deus Ex Machina that helps the main character or hero get out of the incoming peril in some way. This can be simply the warning that the area is dangerous, but sometimes the hero may find useful items left by the victims.

Films -- Live-Action

 * In Star Wars VI: Return of the Jedi, Luke Skywalker gets thrown into the Rancor pit. He is only able to escape its clutches by wedging the femur of a previous victim in its jaws, and after running towards the emergency escape door, he uses the skull of yet another previous victim to activate the great door, which closes on the monster's neck, killing it.
 * King Kong (2005), upon being taken by King Kong back to his cave, Ann Darrow notices many human skeletons on the ground with the same ritual necklace she had put on her when the natives offered her as a sacrifice to the great ape. GASP. Things don't look good, Ann.
 * Jurassic Park: When Ellie Sattler is being tracked by one of the raptors, she feels the reassuring arm of Mr Arnold (Samuel L. Jackson's character) touch her on the shoulder. Unfortunately, that's all there is left of him.
 * In Monty Python and The Holy Grail, King Arthur and his men have a tough time believing that the diminuitive Killer Rabbit they face is dangerous, in spite of all the bones they see littered about the front of his cave. It's not until one of their number gets decapitated by said rabbit that they start to take it seriously.
 * Another scene from that movie features Brave Sir Robin heading down a road which had three signs marked "Certain Death" pointing in the direction he was travelling, several slaughtered knights skewered on the same lance and stuck into a tree, all leading up to the easily avoidable encounter with the three-headed giant, described in the Album of the Soundtrack of the Trailer of the Film as "the fiercest creature for yards around!"
 * In The Mummy Returns, when Imhotep and his followers come arrive at the Scorpion King's oasis, they come across the corpses of soldiers ranging from Roman Legionaires to Napoleon's own troops. Naturally, because Imhotep's followers are literally an army of Red Shirt Mooks, they continue on anyways to their horrible demise.
 * In Clash of the Titans, Perseus and his companions arrive on the island where Medusa has her lair, with numerous petrified victims littering the grounds. One companion scoffs and claims they could just be statues.
 * In the opening sequence of Raiders of the Lost Ark, Indiana and Satipo run across several dessicated corpses inside the ancient shrine. Most memorable of all, Indy's old rival, Forrestal.
 * In The Goonies, the characters run across the long-dead body of treasure hunter Chester Copperpot in their search for One-Eyed Willy's ship. Some of them want to turn back, but Mikey convinces them that this is a good sign, because it means that they're on the right track, and they have already got farther than a professional treasure hunter.
 * Parodied in Scary Movie when a character is faced with an actual road sign clearly marked 'Death', and still follows it.
 * The Lord of the Rings makes it clear to the audience (and most of the characters) that something very bad has happened in Moria with skeletons sprawled on the floor everywhere not far from the entrance. Gimli, however, remains steadfast in his denial until confronted with an actual written account of the bloodbath.

Literature

 * Discworld: Played in a typically Genre Savvy way during Teppic's encounter with the Sphinx in Pyramids. He sees that many people have died nearby, and assumes that the later ones saw the remains of the earlier ones, and tried stealth, and that didn't work. So he doesn't bother being stealthy.

Live-Action TV
"Petracles: Did the map mention how those guys died?
 * Somewhat parodied in the Red Dwarf episode "Psirens". The crew pilot Starbug into a graveyard of ships that have all been crashed or disabled by the titular illusion generating creatures. Sending a scout droid to investigate one of the ships they see (but we don't) the body of a man who had been disemboweled and used his last moments to write "PSIRENS." using a combination of blood and his own intestines. The Cat comments on how impressive it is that the man even used his kidney as a full stop but the other postulate that he probably didn't mean to and it just flopped out there coincidentally.
 * In the Xena: Warrior Princess episode "A Fistful Of Dinars" they have to pass through a "hall of silence"-- a cave filled with dead bodies:

Xena: [Whispers] They made too much noise. [Yells] RUN!"

Videogames

 * In the video-game, Half Life, most instances of danger are introduced with Innocent Bystanders being killed before your very eyes. In the Xen levels, this job is performed by HEV suit-clad corpses.
 * The Temple of the Ocean King, the central dungeon of The Legend of Zelda: Phantom Hourglass, has many skeletons of previous adventurers scattered through its halls. In an interesting variation, all of them still retain their spirits, who will give you clues to help succeed where they failed.
 * Then there's the Shadow Temple from Ocarina of Time...
 * The ruins of La-Mulana are filled with skeletons of previous adventurers. Some are clustered around traps; others hold various messages.
 * Used to the logical extreme in Demons Souls. The player can see the bloodstains of fallen heroes (other players online at the same time), including watching their final moments, and read the messages and warnings left behind by them.
 * Etrian Odyssey III: The Drowned City uses this while the Player Party is helping track an adversary through an area filled with FOEs. At one point, they discover the body of a guard whose armor has been completely shredded, hinting that they're on the right path to reach the next floor. Examining the body after this reveals an item which can be used to.

Western Animation
"First voice on black box: Captain, the bees have us surrounded! Oh, the Professor was right, we're not as good as his old crew!
 * In an episode of Courage the Cowardly Dog Eustace is kidnapped by an underwater witch. Courage pursues and upon reaching the witch's palace peeks on her flirting with Eustace and putting a coral necklace on him. This alone doesn't startle Courage until he notices heaps of skeletons around the palace, each wearing the same necklace.
 * In Samurai Jack, the pathway to a time portal is littered with thousands of skeletons, some even as big as skyscrapers. The source of them is soon shown to be the portal's unbeatable guardian, who even proves to be a challenge for Jack.
 * In Futurama, Leela insists on going on the same mission to collect honey from vicious space bees that resulted in the death of all the Professor's previous crews. Along the way they find the previous crew's ship and check the black box:

Second voice on black box: Well, I aim to prove him wrong! It'll take more than a few deadly deadly bees to-- Oh Lord!

(Sound of screaming. Leela turns off the tape.)

Leela: Uh, couldn't make that out. Too much static."

"Princess Fiona: You didn't slay the dragon?!
 * Before sentenced to "death by snu-snu", Fry, Brannigan and Kif see several previous victims, now skeletons with broken pelvises; some are smoking cigarettes.
 * In the film Atlantis: The Lost Empire, the explorers come across a field of sunken ships ranging from Greek triremes to more modern iron ships shortly before being attacked a gigantic robot.
 * The Spongebob SquarePants Movie, when Spongebob and Patrick go to buy ice cream from an old lady in a stand, right in the middle of piles of bones all around it. Ignoring the danger, Spongebob wades through the bones. Patrick looks at the bones, then looks at Spongebob, and cries out "SPONGEBOB!". Spongebob turns around, and Patrick says "...Make mine chocolate."
 * Shrek, when Shrek and Donkey find Fiona's castle, there are a few humourous instances where we see the remains of previous would-be rescuers littered around the deserted halls.

Shrek: It's on my "to do" list. Now come on!

Princess Fiona: But this isn't right! You're meant to charge in, sword drawn, banner flying -- that's what all the other knights did!

(cut to skeletal remnants of a would-be knight)

Shrek: Yeah, right before they burst into flame!"

Webcomics

 * Sequential Art: At one point Kat and Vanity are below a mansion. Kat follows Vanity who insists there's an opening nearby and keeps marching as if possessed. Kat manages to pan her flashlight to her left just long enough to notice a decent collection of skulls.
 * Spoofed in The Order of the Stick when the party passes through "the Passageway of Horrible Death For Other People" which is littered with arrow-riddled skeletons.