"Ax? It's not a hologram," Rachel said.
<Then ... we are underwater? Protected only by badly made human plastic?>
<Why do you humans do things like this?>
A Video Game Setting consisting of an underwater tunnel with glass walls. Expect to see all sorts of fish and aquatic life on the other side of the glass. Actual sharks are common, but not required.
Truth in Television, as underwater tunnels are very popular features in aquariums worldwide, and more often than not are actually stocked with a few reef sharks as part of the ecosystem in the tank the tunnel runs through.
- The minecart in Riven goes through one on its way from Jungle to Crater Island. Later, there's the underwater viewing room on Survey Island.
- In Super Metroid, Brinstar has a section where it crosses over Maridia, where a short glass tube separates them. A well placed Power Bomb shatters the glass, allowing more free travel between the two. As a Call-Forward, Metroid: Zero Mission's expanded endgame features a similar (albeit not underwater) glass tube connecting the Space Pirate Mothership and the ruins of the temple in Chozodia, which can also be shattered with a Power Bomb after you've reacquired your power suit from the temple to open a way back to the rest of Zebes.
- It makes an appearance in Onimusha 2: Samurai's Destiny and Onimusha 3: Demon Siege. In the former, if you stand still near the glass and absorb souls for a while, a large shark will appear and chomp a school of smaller fish, giving you yellow souls.
- Jaws Unleashed: Yes, the protagonist is on the outside of the tunnel.
- MediEvil has The Lake, in which you walk through a tunnel of water, magically frozen in place by crystals. Outside are huge, blue elephant fish, which constantly trumpet as they swim around.
- Doctor Octopus's lair in Spider-Man (2000).
- Half-Life: Opposing Force has these in the "Crush Depth" level.
- BioShock has a lot of these tunnels linking the habitats of Rapture, with one tunnel featured early-on in an impressive set-piece where a wrecked plane crashes into the tunnel and starts flooding it.
- At least one level of Jedi Knight: Mysteries of the Sith features one, only with Drugons. Oh, and you are in the pool with them and must find your way inside in order to proceed.
- Shadow Warrior (1997) has this as part of the undersea enemy base in the "Water Torture" level. You first see it from the outside as you dive into the waters, and later get to walk through it.
- World of Warcraft has one of these, albeit as a mode of transportation and not an actual combat zone, called the Deeprun Tram.
- Earthworm Jim: While its name suggests a Down the Drain level, the Down The Tubes level is very much a Shark Tunnel.
- In the first level of Gimmick!
- Pulseman: The Australia level of Pulseman had a part like this.
- Sonic Colors: In the Wii version, Sonic goes through such a tunnel at the very beginning of Aquarium Park Act 1. This is because Aquarium Park is set underneath a series of massive interconnected undersea geodesic domes. Sonic arrived from the surface of the water. The DS version does not have such a thing, immediately starting Sonic underneath the domes.
- Sonic Lost World: In the Wii U version, Tropical Coast Act 3 and Lava Mountain Act 2 are set entirely in an underwater tunnel. Also combined with Minecart Madness due to Sonic grinding on rails for almost the entirety of both stages and the presence of minecarts transporting gold and, for some reason, active bombs.
- Duck Rogers for the Super Nintendo has the second world being Under the Sea with a combination of Underwater Ruins, laboratories and interconnecting... well, this trope.
- The Lost Precursor City from Jak and Daxter The Precursor Legacy.
- Planet Aquatos from Ratchet & Clank: Up Your Arsenal.
- In Star Wars Episode I: Racer, the Aquilaris track has these linking the various floating cities.
- The Beginner course in Scud Race / Sega Super GT has two of these, the first of which is called the "Dolphin Tunnel".
- Big Blue 1 in F-Zero GX, which borrows heavily from Scud Race's Beginner course, also has an aquarium tunnel.
- Stunt Race FX: Even with the blocky early polygonal graphics, the track Aqua Tunnel has one, with sharks and sunken ships visible.
- Extreme-G 2. It's not surprising that another futuristic racing game has a shark tunnel in it, with the best examples being Aquanor and Hydra Prime.
- Mario Kart Wii's Koopa Cape track (using giant eels instead of sharks), which was then averted when it reappeared in its successor to fit its new underwater-driving gimmick.
- Ridge Racer 3D's Oceanfront Cruise Way.
- Megarace: The Maeva tracks take place mostly in underwater glass tunnels.
- Need for Speed III has an underwater tunnel on the Aquatica course.
- Roo's Tubes from Crash Team Racing and Deep Sea Driving from Crash Nitro Kart
- Cruisin' USA and its Spiritual Successor California Speed both have a track with this.
- Sonic and Sega All-Stars Racing:
- The "Ocean Ruin" track. It even has a loop-de-loop!
- The sequel has one based on a level from Burning Rangers.
- Sonic Free Riders has one in Dolphin Resort. The earlier game Sonic Riders: Zero Gravity might have one each in Aquatic Capital and Tempest Waterway, but the camera angles when entering are so bizarre that it's not entirely clear if they're underwater or just in a glass tunnel.
- Wipeout Pulse's Vostok Reef.
- Qoron IV in 64.
- Vineta K in Pure.
- Rollcage Stage II.
- Agent Under Fire's tenth level had James Bond riding an open-top tram through a network of underwater tunnels running throughout Malprave Industries' elaborate underwater cloning research lab (known as "Poseidon") in the South China Sea, as Bond must chase down The Dragon, Adrian Malprave's right-hand man Nigel Bloch.
- Sin and Punishment 2's 3rd stage is one that is pretty much made of nothing more than air that's been "dug" through the ocean.
- Animorphs 15: The team ends up in one of these while trying to acquire sharks for their next mission. Ax assumes it's just an enormous screen and is surprised to learn that they're actually surrounded by sharks with only "poorly-made human plastic" protecting them. When they get caught by a Controller, Marco asks Ax "Just how poorly made is human plastic?" and Ax smashes the glass with his tail-blade.
- Jaws 3D has an underwater tunnel that gets attacked by the shark.
- Truth in Television: The original shark tunnel is the one at the Shark Encounter exhibit, at SeaWorld of Florida, Orlando.
- In the "Unfinished Business" season of The Amazing Race, there's a Roadblock where one member of each team has to dive into a tank of this type in order to find their clue.
- The underwater train stations in Dinosaur Train.
- The aquaculture train car in Snowpiercer is one huge marine tank with a tunnel through it. There aren't any sharks visible among the fish it houses, but there are large rays which are at least in the same Class.
- Atlantis resort in Bermuda has a waterslide that goes through a shark tunnel.
- The Georgia Aquarium in Atlanta has a huge tank with one of these through it; the tank includes several huge rays and sharks, including one of the world's only captive whale sharks, the largest species of fish alive today. It's...kinda creepy when it passes overhead.
- Deep Sea World in North Queensferry, Scotland, has one of the world's longest. The tank is mostly home to species found around the coast of Scotland, but also includes a collection of sand tiger sharks, presumably largely for the coolness factor.
- The tank at the Oregon Coast Aquarium which used to hold Keiko the killer whale (of Free Willy fame) has since been converted into one of these. It hosts only sharks, rays, and bony fish found off the Oregon coast in three separate environments (Orford Reef, Halibut Flats, and Open Seas).
- The Oceanarium in Bournemouth, UK has one of these.
- Some of the larger customized aquariums constructed on Animal Planet's Tanked have arches or viewing-bubbles that humans can enter to be surrounded by their fish (although usually not sharks).
- Marine World/Africa USA (Now known as Six Flags Discovery Kingdom) in Northern California introduced its iconic Shark Experience tunnel in 1992.
- Adventure Aquarium in Camden, NJ has a tunnel going through their Shark Realm exhibit.
- There are various aquatic parks in Asia with underwater tunnels featured as main attractions as well, including S.E.A. Aquarium (Sentosa Island, Singapore), Underwater World (Langkawi Island, Malaysia), and various others in Hong Kong, Japan and Taiwan.