Underground spaces represent one of the most underexplored, yet design-rich, layers of any Rockstar Games open world. For Grand Theft Auto VI (GTA VI), which is set in the fictional State of Leonida, a Florida-and-Georgia-inspired landmass (Rockstar Games, 2025; GTA Wiki, 2026), the subterranean dimension poses both creative opportunities and unique technical constraints. Florida's actual geology—a karst limestone platform riddled with sinkholes, underwater caves, springs, and a notoriously high water table (Wikipedia, 2025a)—directly limits what can plausibly exist beneath the streets of Vice City. There are no functional subway systems, no deep basements, and no extensive natural cave networks comparable to those of Liberty City or San Andreas. This report synthesises three classes of underground space likely or possible in Leonida: (1) sewers and stormwater drainage infrastructure, (2) service and utility tunnels (including casino, port, and military), and (3) basements, hurricane shelters, and karst caves; benchmarked against the cave precedent established in Red Dead Redemption 2 (RDR2).
Leonida is explicitly modelled on Florida, with topographic influences from Georgia in its north (GTA Wiki, 2026). Florida is part of the Florida Platform, a carbonate plateau overlain by sandy soils, with the limestone bedrock sitting only metres below the surface across much of the peninsula (Wikipedia, 2025a). The result is a state-wide karst landscape: "Extended systems of underwater caves, sinkholes and springs are found throughout the state and supply most of the water used by residents" (Wikipedia, 2025a). The water table sits at or near the surface in the south; in real Miami, graves are above ground and basements are extremely rare because excavation hits water within feet. This geological constraint is the single most important determinant of underground design in GTA VI. Unlike Los Santos (which sits on solid coastal-range bedrock and hosts an extensive freeway-tunnel and storm-drain network in Grand Theft Auto V), Vice City cannot plausibly support deep tunnels in its southern districts. The northern half of Leonida, however—Mount Kalaga National Park, Port Gellhorn, and the inland counties (Kelly, Leonard, Ambrosia)—straddles Florida/Georgia-style elevation and could plausibly host natural caves analogous to real Florida Caverns State Park or the Devil's Millhopper sinkhole (Wikipedia, 2025a).
Vice City's real-world counterpart, Miami, relies on a combined sewer-and-stormwater system whose visible "outfall" canals and oversized box culverts are a defining feature of South Florida's flat coastal urbanism. In GTA VI, sewer and drainage tunnels are the most plausible large-scale underground spaces in the urban core. Rockstar has historical form here: GTA III and GTA V both used sewer tunnels as discrete linear gameplay spaces for missions and Easter eggs. For Vice City in particular, the second trailer's opening line—Jason "fixing some leaks"—was widely interpreted as a meta-reference (PC Gamer, 2025, as cited in Wikipedia, 2025b) but also signals Rockstar's awareness of water-infrastructure aesthetics. Hurricane-related stormwater pump stations (modelled on Miami-Dade's actual pump fleet) and the perpetually overflowing canal system offer space for chase sequences, drug-stash hides, and gang hideouts under highway overpasses. Storm drains running from the elevated I-95-equivalent down to Biscayne-equivalent outfalls provide the corridor-style underground gameplay that Rockstar has used since 2001.
Where deep basements fail, lateral utility tunnels succeed. Three plausible categories exist:
True residential basements remain rare due to the water table, but the design language can be substituted with:
Red Dead Redemption 2 (Rockstar Games, 2018) set a high bar for natural underground spaces. Caves such as Beryl's Dream, Window Rock, and the Elysian Pool are hand-crafted, atmospherically lit, often hide collectibles (dinosaur bones, rock carvings) or stranger-mission triggers (e.g., the hermit at Manito Glade's adjacent cave). They are short, vertical, and curated rather than sprawling labyrinths—a deliberate design choice rewarding exploration without exhausting players. For GTA VI, this precedent suggests Leonida's northern wilderness areas (Mount Kalaga, the swampy Grassrivers Everglades stand-in) will likely contain a curated set of caves and sinkholes, each tied to a unique stranger encounter, collectible, or environmental story—not an open dungeon system. RDR2's approach favoured discrete, high-quality spaces over quantity, and that philosophy maps cleanly onto Florida's karst features.
The underground layer of Leonida will likely be defined by horizontal sewers and service tunnels in the urban south, scattered hurricane bunkers and stilted under-house spaces in the Keys, and a handful of curated karst caves and sinkholes in the northern wilderness. Deep subway networks remain implausible; the absence of a Vice City metro is itself a worldbuilding statement reinforcing the city's car-culture identity, paralleling Miami's real lack of heavy rail beneath downtown. Expect Rockstar to lean into the visual contrast between sun-baked surfaces and dim, water-stained underground corridors as both gameplay-pacing tool and tonal device, a technique perfected in RDR2 and GTA V.
GTA Wiki (2026) State of Leonida. Available at: https://gta.fandom.com/wiki/State_of_Leonida (Accessed: 14 May 2026).
Rockstar Games (2018) Red Dead Redemption 2. New York: Rockstar Games.
Rockstar Games (2020) Grand Theft Auto Online: The Cayo Perico Heist. New York: Rockstar Games.
Rockstar Games (2025) Grand Theft Auto VI – Official Website. Available at: https://www.rockstargames.com/VI (Accessed: 14 May 2026).
Wikipedia (2025a) Geology of Florida. Available at: https://en.wikipedia.org/wiki/Geology_of_Florida (Accessed: 14 May 2026).
Wikipedia (2025b) Grand Theft Auto VI. Available at: https://en.wikipedia.org/wiki/Grand_Theft_Auto_VI (Accessed: 14 May 2026).