There are many different types of caves on earth. They can be formed by several different geological processes, and their length can range from several feet to hundreds of miles. Some caves are safe and spacious enough to easily accommodate guided tours, while others require special equipment to traverse and explorers face significant risk of becoming stuck and stranded inside them.
Even at their most accommodating, traveling through cave complexes is almost never a convenient way to get from one above-ground location to another.
In fiction, however, cave complexes are frequently treated as effective routes between overland destinations. Particularly in video games, which benefit from geographic chokepoints to keep players on track, cave systems will be used as necessary detours when the usual route between locations is unavailable, or even as the sole established passage between locations. Even when they are permanent, necessary passages, they will generally receive little or no maintenance to make them convenient for travelers.
Used to excess in Lufia & The Fortress of Doom, which contains more than a dozen caves, most of which must be traveled through to get from one place to the next. Caves form chokepoints between countries, and it's even necessary to pass through a cave to reach the house of Guy, one of the heroes who defeated the Sinistrals in their first appearance, who has probably spent so much of his adventuring life in caves that he felt compelled to live near one.
Lufia II: Rise of the Sinistrals uses this less frequently than its predecessor; the heroes still have to travel through many caves in the course of their journey, but only a few of them are passages between locations rather than necessary stops on the way.
Final Fantasy IV has the Cave of Mist, which must be passed through to reach Mist Village. Considering that the king of Baron has it in for them, the Mistians may have good reason for living somewhere hard to get to.
Final Fantasy VI has Figaro Cave, which separates North and South Figaro. The alternate route also happens to be underground, via the sand-burrowing Figaro Castle.
Final Fantasy VII has the Mythril Mine, which is presumably not a natural cave complex, but neither does it seem designed to accommodate traffic, as you might imagine the sole land route between Midgar and Junon, two of the world's most populous cities, would be.
In Final Fantasy IX, in order to travel from Lindblum to Burmecia, the party must pass through Gizmaluke's Grotto. Presumably before Burmecia was attacked by Alexandria, the standard means of transportation between the countries would have been by airship.
In Final Fantasy XII, the only way to reach the capital city of Archades from the Tchita Uplands is through the Sochen Cave Palace, a palace apparently built inside a natural cave system (possibly for the purpose of housing the gigantic dragon living inside.) The Zertinan Caverns also connect many land destinations, but it's only strictly necessary to pass through them for the purposes of various sidequests.
In Tales of Destiny, the party has to pass through a tidal cave to get from the city of Sheeden to the city of Moreau.
In Tales of Eternia, the only way to walk from the city of Mintche to the town of Morle is through the Nostos Cave. Mintche and Morle are on different continents, so it's unsurprising that there's no easy land route from one to the other- except that ordinary citizens aren't allowed to travel on the ships between them.
In Paladin's Quest, it's necessary to pass through the mining town of Hagudo to reach the city of Jurayn. Hagudo is inside of a cave system. Possibly the nonhuman inhabitants prefer it that way, although it's even more unsafe than you would imagine, since while the protagonists are trying to pass through, the town is being flooded with magma.
Multiple instances in the Pokémon games. Some of the most notable from Pokémon Red and Blue include Diglett's Cave, Victory Road, and the caves beneath Mount Moon.
Shining Force II had you go through at least two caves in the game, one to get to Peter the Phoenix's hometown and the other to get from South Paramecia to North Paramecia. Of course, you also had to fight monsters stationed in those caves.
In Wild ARMs, two caves form the nexuses between major landmasses, the Mountain Pass (which mainly goes under, rather than over, the mountains,) and the Sand River, which is filled with crisscrossing currents of flowing sand which impede the passage of any traveler.
The only way to access Fort Dragonia, where the In Medias Res beginning of Chrono Cross takes place, is by passing through the caves under Mt. Pyre. Apparently passing through tunnels filled with molten rock is more practical than going over the mountains.
In Breath of Fire II, the Ryu's hometown of Gate can only be reached by passing through a cave which is itself blocked off from the rest of the world by a dense, pathless forest. How Ryu made it out along with his friend Bow before the Time Skip when the two were still small children without getting lost and starving to death is left for the player to puzzle out.
Breath of Fire III features this as a method of last resort. The land route to the protagonists' destination is blocked by a recent volcanic eruption, protagonists go to the trouble of fixing a broken lighthouse in hopes that the only available ship will return, but the ship still fails to arrive. The only remaining alternative is to go right through the volcano.
Present in the very first Eastern RPG, Dragon Quest I features the swamp cave leading to the town of Rimuldar.
Dragon Quest V features a couple of instances. In one case, your party travels through a cave to get under a mountain range, and in another, they take a Mountain Pass which largely goes through, rather than over, the mountains.
In Legend of Legaia, the party is must travel through a cave early in the game to reach Mt Rikuroa.
In Star Ocean 1, the Sylvalant Ruins are only accessible by passing through a cave.
In Inindo, the only way to reach the location of Nobunaga's castle is through an underground passage. Notably, the entrance itself cannot be accessed without engaging in the Turn Based Strategy portion of the game to place a sympathetic lord in charge of the province in which it's located. If Nobunaga controls the province, his soldiers will stop you from entering at all.
In The Fellowship of the Ring, the fellowship travels through the long-abandoned dwarven city of Moria to get to Lothlorien. Notably this is not a matter of convenience; they only resort to Moria after the other two routes they try (an overland route to the Gap of Rohan and the mountain trail over Caradhras) prove to have been blocked by Saruman.
Dungeon Siege has these in abundance, too. To get from one part of the overworld to another (say, from the woods to the desert region), you typically have to go through a long underground dungeon.
Fallout 3 has the Washington Metro, whose many partially collapsed subway tunnels connect various locations in the ruins of Washington, D.C.
Might and Magic VII has Thunderfist Mountain, which, rather than being a mountain as the name would suggest, is a series of tunnels between three separate mountains scattered around the Mt. Nighon map. The Thunderfist Mountain map leads to two separate "tunnels" maps, the Nighon Tunnels, which lead to the dwarven Stone City underneath the Barrow Downs (several days' walk overland from Mt. Nighon,) and the Tunnels to Eofol, the Land of the Giants. For some reason, a system of tunnels which opens up at the tops of multiple mountains and executes a winding path through the earth, and happens to be filled with some of the most dangerous monsters known to man, is the only feasible method of getting to Eofol. To be fair, anyone who isn't capable of killing some of the most dangerous monsters known to man probably has no business going to the Land of Giants.
Five hats means that five tropers think it is ready to publish.
You are saying that you think this draft is ready to be published. That means the description is not ambiguous,
it doesn't duplicate an existing trope, there are at least three examples, and the title makes sense.
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